Resource Library

This tutorial introduces 9 sources of threat to internal vailidity and asks the user to classify hypothetical experiments as either internally valid or invalid and identify the source of threat if invalid.

This site discusses the issues of reliability and vailidity as related to research.

Gives an overview of variables, classifications, measurements, relations, and other basic statistical concepts. Also contains two animated graphs.

In this applet, A and B are subsets of a universal set S. The list is given of the 16 different subsets of S that can be constructed from A and B using the basic set operations of union, intersection, and complement. The selected subset is colored red in the Venn diagram on the right.

This applet is designed to teach an application of probability. This java applet works by simulating a situation where a three stage rocket is about to be launched. In order for a successful launch to occur all three stages of the rocket must successfully pass their pre-takeoff tests. By default, each stage has a 50% chance of success, however, this can be altered by dragging the bar next to each stage.

Users can test their "psychic ability" to predict the future by guessing the outcome of a coin toss before it occurs. Enter your predictions by clicking the "heads" or "tails" button. When you enter your guess, the coin is tossed and the result is displayed. As you continue guessing, the applet keeps track of the total number of guesses and the total number of correct guesses, plotting it above. If you are truly psychic, you should be able to beat the odds in the long run. You can "weight" the coin by changing the probability of it landing heads.

This program returns a list of all the permutations of the set {1, 2, ..., n}. It allows you to select the given output, copy it, and paste it into a Word or Excel document.

This applet simulates finding confidence intervals for the mean of a normal random variable. A sample of size 20 is generated from a standard normal random variable. The blue marks represent the sample data. The sample mean X and sample standard deviation s are found and used to calculate the confidence interval. The black intervals are the confidence intervals which include the true mean 0, and the red intervals are those which exclude 0. This applet needs to be resized for optimal viewing.

This site explains the 2x2 factorial experimental design, it's components, and it's effects. Graphs illustrate the concepts discussed.

This site lists definitions of key terms related to experimental design and ANOVA, including factorial, blocking, interaction, and others. This site is part of the "Statistics Glossary" for the STEPS project (STatistical Education through Problem Solving).