A cartoon to teach about finding P-values in significance testing. Cartoon by John Landers (www.landers.co.uk) based on an idea from Dennis Pearl (The Ohio State University). Free to use in the classroom and on course web sites.
Compared to probability calculators, the traditional format of distribution tables has the advantage of showing many values simultaneously and, thus, enables the user to examine and quickly explore ranges of probabilities. This webpage includes a list of distributions and tables, including the standard normal (Z) table, student's t table, chi-square table, and F distribution tables. An animation of the density function and distribution function is shown above each distribution table to demonstrate the effects changing degrees of freedom and significance levels have on the shape of a distribution.
This page provides a t-table with degrees of freedom 1-30, 60, 120, and infinity and seven levels of alpha from .1 to .0005.
This page provides a z-table with alpha levels from .00 to .09.
This textbook from VassarStats introduces various statistical topics and contains interactive components. Topics include: Measurement Principles; Distributions; Correlation; Regression; Partial Correlation; Rank-Order Correlation; Statistical Significance; Sampling Distributions; Hypothsis Tests; Probability; Chi-Square; Fisher's Exact Test; t-Distribution; t-test; Mann-Whitney Test; Wilcoxon Signed-Rank Test; Analysis of Variance; F-Distribution; Kruskal-Wallis Test; Friedman Test; Analysis of Covariance. Several calculators and generators include: Binomial Probability; Normal Probability; Binomial Sampling Distribution; Chi-Square Sampling Distribution.
This applet demonstrates the concept of power. Users select the hypothesized mean, the alternative mean, the sample size, and the number of samples. The applet shows the hypothesized histogram and the alternative histogram. Users then select either the level of significance and set alpha or the rejection region and set the test statistic. The applet then shows the p-value (in red) and power (in green). User can also determine the direction of the test by clicking the inequality sign.