Resource Library

This website lists five different types of probability sampling, giving the advantages and disadvantages of each.

A series of pamphlets place online by the American Statistical Association, Survey Research Methods Section. Each pamphlet deals with a different aspect of survey research and how it is done.

The first chapter of an online Introduction to Biostatistics course. Two lecture notes and a set of overheads are provided. Additionally, links for additional reading and exercises with solutions are provided.

A paper discussing the development of construct validity as applied to psychological studies.

This article gives a description of typical sources of error in public opinion polls. It gives a short but insightful explanation of what the margin of error indicates as well as other common errors in opinion polls.

This exercise will help the user understand the logic and procedures of hypothesis testing. To make best use of this exercise, the user should know how to use a z table to find probabilities on a normal distribution, and how to calculate the standard error of a mean. Relevant review materials are available from the links provided. The user will need a copy of the hypothesis testing exercise (link is provided), a table for the standardized normal distribution (z), and a calculator. The user will be asked several questions and will be given feedback regarding their answers. Detailed solutions are provided, but users should try to answer the questions on their own before consulting the detailed solutions. The end of the tutorial contains some "thought" questions.

Students can sample numerous bags of M&Ms. A plot of the relative frequency of each color is continually updated above the sampling frame. Each sample bag of M&Ms contains 56 candies.

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.