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Free Statistics Calculators!
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Welcome to version 3.0 of the Free Statistics Calculators website! These statistics
calculators are free to be used by anyone in the research community at large. They
are offered humbly in the hope that they will contribute in some small way to the
advancement of science and the betterment of mankind. I hope you find them useful!
The statistics calculators are organized into the 29 categories shown below. Clicking
on a category name will display a list of calculators available for that category.
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 | Analysis of Variance (ANOVA) Calculator - One-Way ANOVA from Summary Data  This calculator will generate a complete one-way analysis of variance (ANOVA) table for up to 8 groups, including sums of squares, degrees of freedom, mean squares, and F and p-values, given the mean, standard deviation, and number of subjects in each group. |
 | Analysis of Variance (ANOVA) Intraclass Correlation Calculator  This calculator will compute the intraclass correlation for an analysis of variance (ANOVA) study, given the between-groups mean square, the within-groups mean square, and the number of subjects in each group. |
 | Binomial Coefficient Calculator  This calculator will compute the value of a binomial coefficient, given values of the first nonnegative integer n, and the second nonnegative integer k. |
 | Binomial Probability Calculator  This calculator will compute the probability of an individual binomial outcome (i.e., a binomial probability), given the number of successes, the number of trials, and the probability of a successful outcome occurring. |
 | Binomial Probability Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for a binomial probability, given the number of successes and the total number of trials. This calculator relies on the Clopper-Pearson (exact) method. |
 | Cumulative Binomial Probability Calculator  This calculator will compute cumulative probabilities for a binomial outcome, given the number of successes, the number of trials, and the probability of a successful outcome occurring. For the number of successes x, the calculator will return P(Xx), and P(X>=x). |
 | Cumulative Distribution Function (CDF) Calculator for the Binomial Distribution  This calculator will compute the cumulative distribution function (CDF) for the binomial distribution, given the number of successes, the number of trials, and the probability of a successful outcome occurring. |
 | Expected Value Calculator for a Binomial Random Variable  This calculator will tell you the expected value for a binomial random variable, given the number of trials and the probability of success. |
 | Probability Mass Function (PMF) Calculator for the Binomial Distribution  This calculator will compute the probability mass function (PMF) for the binomial distribution, given the number of successes, the number of trials, and the probability of a successful outcome occurring. |
 | Variance Calculator for a Binomial Random Variable  This calculator will tell you the variance for a binomial random variable, given the number of trials and the probability of success. |
 | Binomial Probability Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for a binomial probability, given the number of successes and the total number of trials. This calculator relies on the Clopper-Pearson (exact) method. |
 | Confidence Interval Calculator for a Predicted Value of a Regression Equation  This calculator will compute the 99%, 95%, and 90% confidence intervals for a predicted value of a regression equation, given a predicted value of the dependent variable, the standard error of the estimate, the number of predictors in the model, and the total sample size. |
 | Confidence Interval Calculator for the Population Mean  This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population, given the sample mean, the sample size, and the sample standard deviation. |
 | Confidence Interval Calculator for the Population Mean (when population std dev is known)  This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population when the population standard deviation is known, given the sample mean, the sample size, and the population standard deviation. |
 | f-square Effect Size Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for the f-square effect size associated with a multiple regression study, given the f-square value, the number of predictors in the model, and the total sample size. |
 | Indirect Mediation Effect Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for an indirect mediation effect, given the regression coefficient and standard error for the relationship between the independent variable and the mediator, and the regression coefficient and standard error for the relationship between the mediator and the dependent variable. |
 | Poisson Confidence Interval Calculator  This calculator will compute the exact 99%, 95%, and 90% confidence intervals for a Poisson mean, given the number of event occurrences. |
 | R-square Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for an R-square value (i.e., a squared multiple correlation), given the value of the R-square, the number of predictors in the model, and the total sample size. |
 | Regression Coefficient Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for a regression coefficient, given the value of the regression coefficient, the standard error of the regression coefficient, the number of predictors in the model, and the total sample size. |
 | Regression Intercept Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for a regression intercept (i.e., the regression constant), given the value of the regression intercept, the standard error of the regression intercept, the number of predictors in the model, and the total sample size. |
 | Analysis of Variance (ANOVA) Intraclass Correlation Calculator  This calculator will compute the intraclass correlation for an analysis of variance (ANOVA) study, given the between-groups mean square, the within-groups mean square, and the number of subjects in each group. |
 | Correlation Coefficient Calculator (from a Covariance)  This calculator will compute the Pearson correlation coefficient r for two variables X and Y, given the covariance value between the two variables, and their standard deviations. |
 | Covariance Calculator (from a Correlation Coefficient)  This calculator will compute the covariance between two variables X and Y, given the Pearson correlation coefficient for the two variables, and their standard deviations. |
 | p-Value Calculator for Correlation Coefficients  This calculator will tell you the significance (both one-tailed and two-tailed probability values) of a Pearson correlation coefficient, given the correlation value r, and the sample size. |
 | t-Value Calculator for Correlation Coefficients  This calculator will tell you the t-value and degrees of freedom associated with a Pearson correlation coefficient, given the correlation value r, and the sample size. |
 | Cumulative Distribution Function (CDF) Calculator for the Beta Distribution  This calculator will compute the cumulative distribution function (CDF) for the beta distribution (i.e., the area under the beta distribution from 0 to x), given values of the shape parameters, and the point at which to evaluate the function. |
 | Cumulative Distribution Function (CDF) Calculator for the Binomial Distribution  This calculator will compute the cumulative distribution function (CDF) for the binomial distribution, given the number of successes, the number of trials, and the probability of a successful outcome occurring. |
 | Cumulative Distribution Function (CDF) Calculator for the Chi-Square Distribution  This calculator will compute the cumulative distribution function (CDF) for the Chi-square distribution, given the point at which to evaluate the function x, and the degrees of freedom. |
 | Cumulative Distribution Function (CDF) Calculator for the F-Distribution  This calculator will compute the cumulative distribution function (CDF) for the Fisher F-distribution (i.e., the area under the F-distribution from 0 to x), given the numerator and denominator degrees of freedom, and the upper limit of integration x. |
 | Cumulative Distribution Function (CDF) Calculator for the Noncentral F-Distribution  This calculator will compute the cumulative distribution function (CDF) for the noncentral F-distribution, given an F-value, the numerator and denominator degrees of freedom, and the noncentrality parameter. |
 | Cumulative Distribution Function (CDF) Calculator for the Noncentral t-Distribution  This calculator will compute the cumulative distribution function (CDF) for the noncentral t-distribution (i.e., the area under the noncentral t-distribution from negative infinity to t), given a t-value, the degrees of freedom, and the value of the noncentrality parameter. |
 | Cumulative Distribution Function (CDF) Calculator for the Normal Distribution  This calculator will compute the cumulative distribution function (CDF) for the normal distribution (i.e., the area under the normal distribution from negative infinity to x), given the upper limit of integration x, the mean, and the standard deviation. |
 | Cumulative Distribution Function (CDF) Calculator for the Poisson Distribution  This calculator will compute the cumulative distribution function (CDF) for the Poisson distribution, given the number of event occurrences and the expected number of event occurrences. |
 | Cumulative Distribution Function (CDF) Calculator for the Standard Normal Distribution  This calculator will compute the cumulative distribution function (CDF) for the standard normal distribution (i.e., the area under the standard normal distribution from negative infinity to x), given the upper limit of integration x. |
 | Cumulative Distribution Function (CDF) Calculator for the t-Distribution  This calculator will compute the cumulative distribution function (CDF) for Student's t-distribution (i.e., the area under the t-distribution from negative infinity to t), given a t-value and the degrees of freedom. |
 | Cumulative Distribution Function (CDF) Calculator for the Uniform Distribution  This calculator will compute the cumulative distribution function (CDF) for the (continuous) uniform distribution, given the values of the upper and lower boundaries of the distribution and the point at which to evaluate the function. |
 | Effect Size (Cohen's d) Calculator for a Student t-Test  This calculator will tell you the (two-tailed) effect size for a Student t-test (i.e., Cohen's d), given the mean and standard deviation for two independent samples of equal size. |
 | Effect Size Calculator for Hierarchical Multiple Regression  This calculator will tell you the effect size for a hierarchical multiple regression study (Cohen's f-square), given an R-square value for a set of independent variables A, and an R-square value for the sum of A and another set of independent variables B. The value returned by the calculator is the effect size attributable to the addition of set B to the model. |
 | Effect Size Calculator for Multiple Regression  This calculator will tell you the effect size for a multiple regression study (i.e., Cohen's f-square), given a value of R-square. |
 | f-square Effect Size Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for the f-square effect size associated with a multiple regression study, given the f-square value, the number of predictors in the model, and the total sample size. |
 | R-square Calculator (from an f-square Effect Size)  This calculator will compute an R-square value for a multiple regression model, given Cohen's f-square effect size for the model. |
 | Complementary Probability Calculator  This calculator will compute the probability that event A will not occur (i.e., the complementary probability of A), given the probability of event A occurring. |
 | Conditional Probability Calculator  This calculator will compute the probability of event A occurring, given that event B has occurred (i.e., the conditional probability of A), given the joint probability of events A and B, and the probability of event B. |
 | Joint Probability Calculator  This calculator will compute the probability of two events A and B occurring together (i.e., the joint probability of A and B), given the conditional probability of event A, and the probability of event B. |
 | Union Probability Calculator  This calculator will compute the probability of event A or event B occurring (i.e., the union probability for A and B), given the probability of event A, the probability of event B, and the joint probability of events A and B. |
 | Critical F-value Calculator  This calculator will tell you the critical value of the F-distribution, given the probability level, the numerator degrees of freedom, and the denominator degrees of freedom. |
 | Cumulative Distribution Function (CDF) Calculator for the F-Distribution  This calculator will compute the cumulative distribution function (CDF) for the Fisher F-distribution (i.e., the area under the F-distribution from 0 to x), given the numerator and denominator degrees of freedom, and the upper limit of integration x. |
 | Cumulative Distribution Function (CDF) Calculator for the Noncentral F-Distribution  This calculator will compute the cumulative distribution function (CDF) for the noncentral F-distribution, given an F-value, the numerator and denominator degrees of freedom, and the noncentrality parameter. |
 | Expected Value Calculator for an F-Distribution Random Variable  This calculator will tell you the expected value (i.e., the mean) for an F-distribution random variable, given the denominator degrees of freedom. |
 | F-Value and p-Value Calculator for Multiple Regression  This calculator will tell you the Fisher F-value for a multiple regression study and its associated probability level (p-value), given the model R-square, the number of predictors in the model, and the total sample size. |
 | F-Value Calculator for Hierarchical Multiple Regression  This calculator will tell you the F-value for a hierarchical multiple regression study, given an R-square value for a set of independent variables A, an R-square value for the sum of A and another set of independent variables B, the number of predictors in A, the number of predictors in B, and the total sample size. The value returned by the calculator is the the F-value associated with the addition of B to the model. |
 | p-Value Calculator for an F-Test  This calculator will tell you the probability value of an F-test, given the F-value, numerator degrees of freedom, and denominator degrees of freedom. |
 | Probability Density Function (PDF) Calculator for the F-Distribution  This calculator will compute the probability density function (PDF) for the Fisher F-distribution, given the numerator and denominator degrees of freedom, and the point at which to evaluate the function x. |
 | Variance Calculator for an F-Distribution Random Variable  This calculator will tell you the variance for an F-distribution random variable, given the numerator and denominator degrees of freedom. |
 | A-priori Sample Size Calculator for Hierarchical Multiple Regression  This calculator will tell you the minimum sample size required for a hierarchical multiple regression analysis; i.e., the minimum sample size required for a significance test of the addition of a set of independent variables B to the model, over and above another set of independent variables A. The value returned by the calculator is the minimum sample size required to detect an effect of the specified size, probability level, and power level for the addition of set B to the model. |
 | Beta (Type II Error Rate) Calculator for Hierarchical Multiple Regression  This calculator will tell you the beta level (the Type II error rate) for a hierarchical regression analysis; i.e., the beta level for a significance test of the addition of a set of independent variables B to the hierarchical model, over and above another set of independent variables A. The value returned by the calculator is the beta level (i.e., the Type II error rate) for the addition of the set of independent variables B to the overall hierarchical model. |
 | Effect Size Calculator for Hierarchical Multiple Regression  This calculator will tell you the effect size for a hierarchical multiple regression study (Cohen's f-square), given an R-square value for a set of independent variables A, and an R-square value for the sum of A and another set of independent variables B. The value returned by the calculator is the effect size attributable to the addition of set B to the model. |
 | F-Value Calculator for Hierarchical Multiple Regression  This calculator will tell you the F-value for a hierarchical multiple regression study, given an R-square value for a set of independent variables A, an R-square value for the sum of A and another set of independent variables B, the number of predictors in A, the number of predictors in B, and the total sample size. The value returned by the calculator is the the F-value associated with the addition of B to the model. |
 | Post-hoc Statistical Power Calculator for Hierarchical Multiple Regression  This calculator will tell you the observed power for a hierarchical regression analysis; i.e., the observed power for a significance test of the addition of a set of independent variables B to the hierarchical model, over and above another set of independent variables A. The value returned by the calculator is the observed power for the addition of the set of independent variables B to the overall hierarchical model. |
 | Indirect Effect Calculator for Mediation Models  This calculator will compute the indirect effect of a mediation model, given the regression coefficient between the independent variable and the mediator variable and the regression coefficient between the mediator variable and the dependent variable. |
 | Indirect Mediation Effect Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for an indirect mediation effect, given the regression coefficient and standard error for the relationship between the independent variable and the mediator, and the regression coefficient and standard error for the relationship between the mediator and the dependent variable. |
 | Sobel Test Calculator for the Significance of Mediation  This calculator uses the Sobel test to tell you whether a mediator variable significantly carries the influence of an independent variable to a dependent variable; i.e., whether the indirect effect of the independent variable on the dependent variable through the mediator variable is significant. This calculator returns the Sobel test statistic, and both one-tailed and two-tailed probability values. |
 | Total Effect Calculator for Mediation Models  This calculator will compute the total effect of a mediation model, given the regression coefficient between the independent variable and the mediator variable, the regression coefficient between the mediator variable and the dependent variable, and the regression coefficient between the independent variable and the dependent variable. |
 | Variance Calculator for an Indirect Mediation Effect  This calculator uses Sobel's multivariate delta method to compute the variance of an indirect effect in a mediation model, given the regression coefficient and standard error for the relationship between the independent variable and the mediator, and the regression coefficient and standard error for the relationship between the mediator and the dependent variable. |
 | Adjusted R-square Calculator (Population R-square)  This calculator will compute an adjusted R-square value (i.e., the population squared multiple correlation), given an observed (sample) R-square, the number of predictors in the model, and the total sample size. |
 | Coefficient of Variation Calculator  This calculator will compute the coefficient of variation for a set of data, given the standard deviation and the mean. |
 | Factorial Calculator  This calculator will compute the factorial for any nonnegative integer value between 0 and 2,000. |
 | Z-score Calculator  This calculator will compute a Z-score (i.e., a standard normal score), given an unstandardized raw value, the population mean, and the standard deviation of the population to which the unstandardized value belongs. |
 | A-priori Sample Size Calculator for Multiple Regression  This calculator will tell you the minimum required sample size for a multiple regression study, given the desired probability level, the number of predictors in the model, the anticipated effect size, and the desired statistical power level. |
 | Adjusted R-square Calculator (Population R-square)  This calculator will compute an adjusted R-square value (i.e., the population squared multiple correlation), given an observed (sample) R-square, the number of predictors in the model, and the total sample size. |
 | Beta (Type II Error Rate) Calculator for Multiple Regression  This calculator will tell you the beta level for your study (i.e., the Type II error rate), given the observed probability level, the number of predictors, the observed R-square, and the sample size. |
 | Confidence Interval Calculator for a Predicted Value of a Regression Equation  This calculator will compute the 99%, 95%, and 90% confidence intervals for a predicted value of a regression equation, given a predicted value of the dependent variable, the standard error of the estimate, the number of predictors in the model, and the total sample size. |
 | Critical F-value Calculator  This calculator will tell you the critical value of the F-distribution, given the probability level, the numerator degrees of freedom, and the denominator degrees of freedom. |
 | Effect Size Calculator for Multiple Regression  This calculator will tell you the effect size for a multiple regression study (i.e., Cohen's f-square), given a value of R-square. |
 | f-square Effect Size Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for the f-square effect size associated with a multiple regression study, given the f-square value, the number of predictors in the model, and the total sample size. |
 | F-Value and p-Value Calculator for Multiple Regression  This calculator will tell you the Fisher F-value for a multiple regression study and its associated probability level (p-value), given the model R-square, the number of predictors in the model, and the total sample size. |
 | Post-hoc Statistical Power Calculator for Multiple Regression  This calculator will tell you the observed power for your multiple regression study, given the observed probability level, the number of predictors, the observed R-square, and the sample size. |
 | R-square Calculator (from an f-square Effect Size)  This calculator will compute an R-square value for a multiple regression model, given Cohen's f-square effect size for the model. |
 | R-square Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for an R-square value (i.e., a squared multiple correlation), given the value of the R-square, the number of predictors in the model, and the total sample size. |
 | Regression Coefficient Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for a regression coefficient, given the value of the regression coefficient, the standard error of the regression coefficient, the number of predictors in the model, and the total sample size. |
 | Regression Intercept Confidence Interval Calculator  This calculator will compute the 99%, 95%, and 90% confidence intervals for a regression intercept (i.e., the regression constant), given the value of the regression intercept, the standard error of the regression intercept, the number of predictors in the model, and the total sample size. |
 | Cumulative Distribution Function (CDF) Calculator for the Noncentral F-Distribution  This calculator will compute the cumulative distribution function (CDF) for the noncentral F-distribution, given an F-value, the numerator and denominator degrees of freedom, and the noncentrality parameter. |
 | Cumulative Distribution Function (CDF) Calculator for the Noncentral t-Distribution  This calculator will compute the cumulative distribution function (CDF) for the noncentral t-distribution (i.e., the area under the noncentral t-distribution from negative infinity to t), given a t-value, the degrees of freedom, and the value of the noncentrality parameter. |
 | Probability Density Function (PDF) Calculator for the Noncentral t-Distribution  This calculator will compute the probability density function (PDF) for the noncentral t-distribution, given a t-value, the degrees of freedom, and the value of the noncentrality parameter. |
 | Confidence Interval Calculator for the Population Mean  This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population, given the sample mean, the sample size, and the sample standard deviation. |
 | Confidence Interval Calculator for the Population Mean (when population std dev is known)  This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population when the population standard deviation is known, given the sample mean, the sample size, and the population standard deviation. |
 | Cumulative Area Under the Standard Normal Curve Calculator  This calculator will tell you the cumulative area under the standard normal distribution, given a z-score (i.e., the cumulative probability from minus infinity to the z-score). |
 | Cumulative Distribution Function (CDF) Calculator for the Normal Distribution  This calculator will compute the cumulative distribution function (CDF) for the normal distribution (i.e., the area under the normal distribution from negative infinity to x), given the upper limit of integration x, the mean, and the standard deviation. |
 | Cumulative Distribution Function (CDF) Calculator for the Standard Normal Distribution  This calculator will compute the cumulative distribution function (CDF) for the standard normal distribution (i.e., the area under the standard normal distribution from negative infinity to x), given the upper limit of integration x. |
 | One-Tailed Area Under the Standard Normal Distribution Calculator  This calculator will tell you the one-tailed (right-tail) area under the standard normal curve, given a Z-score (i.e., the one-tailed probability from the z-score to positive infinity). |
 | Probability Density Function (PDF) Calculator for the Normal Distribution  This calculator will compute the probability density function (PDF) for the normal distribution, given the mean, standard deviation, and the point at which to evaluate the function x. |
 | Probability Density Function (PDF) Calculator for the Standard Normal Distribution  This calculator will compute the probability density function (PDF) for the standard normal distribution, given the point at which to evaluate the function x. |
 | Standard Normal Distribution Z-Score Calculator  This calculator will tell you the normal distribution Z-score associated with a given cumulative probability level. |
 | Two-Tailed Area Under the Standard Normal Distribution Calculator  This calculator will tell you the two-tailed area under the standard normal curve, given a Z-score (i.e., the two-tailed probability from +/- the Z-score to infinity on both tails of the distribution). |
 | Z-score Calculator  This calculator will compute a Z-score (i.e., a standard normal score), given an unstandardized raw value, the population mean, and the standard deviation of the population to which the unstandardized value belongs. |
 | Cumulative Distribution Function (CDF) Calculator for the Poisson Distribution  This calculator will compute the cumulative distribution function (CDF) for the Poisson distribution, given the number of event occurrences and the expected number of event occurrences. |
 | Cumulative Poisson Probability Calculator  This calculator will compute cumulative probabilities for a Poisson outcome, given the total number of events observed, the expected number of events per interval, and the total number of intervals. For the total number of events observed k, the calculator will return P(Kk), and P(K>=k). |
 | Poisson Confidence Interval Calculator  This calculator will compute the exact 99%, 95%, and 90% confidence intervals for a Poisson mean, given the number of event occurrences. |
 | Poisson Probability Calculator  This calculator will compute a Poisson probability (i.e., the probability of a specific number of events occurring within a specific number of fixed intervals of time or space), given the total number of events observed, the expected number of events per interval, and the total number of intervals. |
 | Probability Mass Function (PMF) Calculator for the Poisson Distribution  This calculator will compute the probability mass function (PMF) for the Poisson distribution, given the number of event occurrences and the expected number of event occurrences. |
 | Binomial Probability Calculator  This calculator will compute the probability of an individual binomial outcome (i.e., a binomial probability), given the number of successes, the number of trials, and the probability of a successful outcome occurring. |
 | Complementary Probability Calculator  This calculator will compute the probability that event A will not occur (i.e., the complementary probability of A), given the probability of event A occurring. |
 | Conditional Probability Calculator  This calculator will compute the probability of event A occurring, given that event B has occurred (i.e., the conditional probability of A), given the joint probability of events A and B, and the probability of event B. |
 | Cumulative Area Under the Standard Normal Curve Calculator  This calculator will tell you the cumulative area under the standard normal distribution, given a z-score (i.e., the cumulative probability from minus infinity to the z-score). |
 | Cumulative Binomial Probability Calculator  This calculator will compute cumulative probabilities for a binomial outcome, given the number of successes, the number of trials, and the probability of a successful outcome occurring. For the number of successes x, the calculator will return P(Xx), and P(X>=x). |
 | Cumulative Poisson Probability Calculator  This calculator will compute cumulative probabilities for a Poisson outcome, given the total number of events observed, the expected number of events per interval, and the total number of intervals. For the total number of events observed k, the calculator will return P(Kk), and P(K>=k). |
 | F-Value and p-Value Calculator for Multiple Regression  This calculator will tell you the Fisher F-value for a multiple regression study and its associated probability level (p-value), given the model R-square, the number of predictors in the model, and the total sample size. |
 | Fisher's Exact Test Calculator for a 2x2 Contingency Table  This calculator will compute both the exact hypergeometric probability and the exact two-tailed probability of obtaining a distribution of values in a 2x2 contingency table using Fisher's exact test, given the number of observations in each cell. |
 | Fisher's Exact Test Calculator for a 2x3 Contingency Table  This calculator uses the Freeman-Halton extension of Fisher's exact test to compute the (two-tailed) probability of obtaining a distribution of values in a 2x3 contingency table, given the number of observations in each cell. |
 | Fisher's Exact Test Calculator for a 3X3 Contingency Table  This calculator uses the Freeman-Halton extension of Fisher's exact test to compute the (two-tailed) probability of obtaining a distribution of values in a 3x3 contingency table, given the number of observations in each cell. |
 | Interval Probability Calculator for the Uniform Distribution  This calculator will compute the probability of a specified interval under a (continuous) uniform distribution, given the values of the upper and lower boundaries of the distribution and the values of the upper and lower boundaries of the probability interval. |
 | Joint Probability Calculator  This calculator will compute the probability of two events A and B occurring together (i.e., the joint probability of A and B), given the conditional probability of event A, and the probability of event B. |
 | One-Tailed Area Under the Standard Normal Distribution Calculator  This calculator will tell you the one-tailed (right-tail) area under the standard normal curve, given a Z-score (i.e., the one-tailed probability from the z-score to positive infinity). |
 | p-Value Calculator for a Chi-Square Test  This calculator will tell you the one-tailed (right-tail) probability value for a chi-square test (i.e., the area under the chi-square distribution from the chi-square value to positive infinity), given the chi-square value and the degrees of freedom. |
 | p-Value Calculator for a Student t-Test  This calculator will tell you the one-tailed and two-tailed probability values of a t-test, given the t-value and the degrees of freedom. |
 | p-Value Calculator for an F-Test  This calculator will tell you the probability value of an F-test, given the F-value, numerator degrees of freedom, and denominator degrees of freedom. |
 | p-Value Calculator for Correlation Coefficients  This calculator will tell you the significance (both one-tailed and two-tailed probability values) of a Pearson correlation coefficient, given the correlation value r, and the sample size. |
 | Poisson Probability Calculator  This calculator will compute a Poisson probability (i.e., the probability of a specific number of events occurring within a specific number of fixed intervals of time or space), given the total number of events observed, the expected number of events per interval, and the total number of intervals. |
 | Sobel Test Calculator for the Significance of Mediation  This calculator uses the Sobel test to tell you whether a mediator variable significantly carries the influence of an independent variable to a dependent variable; i.e., whether the indirect effect of the independent variable on the dependent variable through the mediator variable is significant. This calculator returns the Sobel test statistic, and both one-tailed and two-tailed probability values. |
 | Two-Tailed Area Under the Standard Normal Distribution Calculator  This calculator will tell you the two-tailed area under the standard normal curve, given a Z-score (i.e., the two-tailed probability from +/- the Z-score to infinity on both tails of the distribution). |
 | Union Probability Calculator  This calculator will compute the probability of event A or event B occurring (i.e., the union probability for A and B), given the probability of event A, the probability of event B, and the joint probability of events A and B. |
 | Probability Density Function (PDF) Calculator for the Beta Distribution  This calculator will compute the probability density function (PDF) for the beta distribution, given values of the shape parameters and the point at which to evaluate the function. |
 | Probability Density Function (PDF) Calculator for the Chi-Square Distribution  This calculator will compute the probability density function (PDF) for the Chi-square distribution, given the point at which to evaluate the function x, and the degrees of freedom. |
 | Probability Density Function (PDF) Calculator for the F-Distribution  This calculator will compute the probability density function (PDF) for the Fisher F-distribution, given the numerator and denominator degrees of freedom, and the point at which to evaluate the function x. |
 | Probability Density Function (PDF) Calculator for the Noncentral t-Distribution  This calculator will compute the probability density function (PDF) for the noncentral t-distribution, given a t-value, the degrees of freedom, and the value of the noncentrality parameter. |
 | Probability Density Function (PDF) Calculator for the Normal Distribution  This calculator will compute the probability density function (PDF) for the normal distribution, given the mean, standard deviation, and the point at which to evaluate the function x. |
 | Probability Density Function (PDF) Calculator for the Standard Normal Distribution  This calculator will compute the probability density function (PDF) for the standard normal distribution, given the point at which to evaluate the function x. |
 | Probability Density Function (PDF) Calculator for the t-Distribution  This calculator will compute the probability density function (PDF) for Student's t-distribution, given a t-value and the degrees of freedom. |
 | Probability Density Function (PDF) Calculator for the Uniform Distribution  This calculator will compute the probability density function (PDF) for the (continuous) uniform distribution, given the values of the upper and lower boundaries of the distribution and the point at which to evaluate the function. |
 | A-priori Sample Size Calculator for Hierarchical Multiple Regression  This calculator will tell you the minimum sample size required for a hierarchical multiple regression analysis; i.e., the minimum sample size required for a significance test of the addition of a set of independent variables B to the model, over and above another set of independent variables A. The value returned by the calculator is the minimum sample size required to detect an effect of the specified size, probability level, and power level for the addition of set B to the model. |
 | A-priori Sample Size Calculator for Multiple Regression  This calculator will tell you the minimum required sample size for a multiple regression study, given the desired probability level, the number of predictors in the model, the anticipated effect size, and the desired statistical power level. |
 | A-priori Sample Size Calculator for Structural Equation Models  This calculator will compute the sample size required for a study that uses a structural equation model (SEM), given the number of observed and latent variables in the model, the anticipated effect size, and the desired probability and statistical power levels. The calculator will return both the minimum sample size required to detect the specified effect, and the minimum sample size required given the structural complexity of the model. |
 | A-priori Sample Size Calculator for Student t-Tests  This calculator will tell you the minimum required total sample size and per-group sample size for a one-tailed or two-tailed t-test study, given the probability level, the anticipated effect size, and the desired statistical power level. |
 | A-priori Sample Size Calculator for Student t-Tests  This calculator will tell you the minimum required total sample size and per-group sample size for a one-tailed or two-tailed t-test study, given the probability level, the anticipated effect size, and the desired statistical power level. |
 | Beta (Type II Error Rate) Calculator for a Student t-Test  This calculator will tell you the beta level for a one-tailed or two-tailed t-test study (i.e., the Type II error rate), given the observed probability level, the observed effect size, and the total sample size. |
 | Confidence Interval Calculator for the Population Mean  This calculator will compute the 99%, 95%, and 90% confidence intervals for the mean of a normal population, given the sample mean, the sample size, and the sample standard deviation. |
 | Cumulative Distribution Function (CDF) Calculator for the Noncentral t-Distribution  This calculator will compute the cumulative distribution function (CDF) for the noncentral t-distribution (i.e., the area under the noncentral t-distribution from negative infinity to t), given a t-value, the degrees of freedom, and the value of the noncentrality parameter. |
 | Cumulative Distribution Function (CDF) Calculator for the t-Distribution  This calculator will compute the cumulative distribution function (CDF) for Student's t-distribution (i.e., the area under the t-distribution from negative infinity to t), given a t-value and the degrees of freedom. |
 | Effect Size (Cohen's d) Calculator for a Student t-Test  This calculator will tell you the (two-tailed) effect size for a Student t-test (i.e., Cohen's d), given the mean and standard deviation for two independent samples of equal size. |
 | One-Sample t-Test Calculator  This calculator will conduct a complete one-sample t-test, given the sample mean, the sample size, the hypothesized mean, and the sample standard deviation. The results generated by the calculator include the t-statistic, the degrees of freedom, the critical t-values for both one-tailed (directional) and two-tailed (non-directional) hypotheses, and the one-tailed and two-tailed probability values associated with the test. |
 | p-Value Calculator for a Student t-Test  This calculator will tell you the one-tailed and two-tailed probability values of a t-test, given the t-value and the degrees of freedom. |
 | Post-hoc Statistical Power Calculator for a Student t-Test  This calculator will tell you the observed power for a one-tailed or two-tailed t-test study, given the observed probability level, the observed effect size, and the total sample size. |
 | Probability Density Function (PDF) Calculator for the Noncentral t-Distribution  This calculator will compute the probability density function (PDF) for the noncentral t-distribution, given a t-value, the degrees of freedom, and the value of the noncentrality parameter. |
 | Probability Density Function (PDF) Calculator for the t-Distribution  This calculator will compute the probability density function (PDF) for Student's t-distribution, given a t-value and the degrees of freedom. |
 | Student t-Value Calculator  This calculator will tell you the Student t-value for a given probability and degrees of freedom. Student t-values for both one-tailed (right-tail) and two-tailed probabilities will be returned. |
 | t-Statistic and Degrees of Freedom Calculator  This calculator will compute the t-statistic and degrees of freedom for a Student t-test, given the sample mean, the sample size, the hypothesized mean, and the sample standard deviation. |
 | t-Value Calculator for Correlation Coefficients  This calculator will tell you the t-value and degrees of freedom associated with a Pearson correlation coefficient, given the correlation value r, and the sample size. |
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