A cartoon to teach about the measurement issues of bias, reliability, and validity. 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.
This module is designed to illustrate the effects of selection bias on the observed relationship between premarital cohabitation and later divorce. It also serves as a review of key methodological concepts introduced in the first part of the course.
This is a three day lesson plan. The first day is an introduction to concepts in probability. The second day is an application of probability in the field of genetics. The third day is a time for students to expand their understanding of probability and genetics via short research project. The site includes resources, advice, and notes to the teacher. Probability topics include: law of large numbers, simple and compound events, sample size, sample space, and more.
This paper presents rules for determining whether an index variable in such a table is part or whole depending on whether the associated margin value is an average, a sum or a 100% sum. Tables with missing margin values -- date-indexed tables, half tables and control tables -- are analyzed. Recommendations are made to improve reader understanding of any table involving rates or percentages.
This article provides the example of student form orders to demonstrate the unreliability of combining data from two different distributions (or subjects).
This website provides links to instructions for performing basic statistics such as confidence intervals, hypothesis tests, discrete distributions, linear regression, etc. for TI 83, TI 84, and TI 86 calculators.
This article describes a dataset on life expectancies, densities of people per television set, and densities of people per physician in various countries of the world. The example addresses correlation versus causation and data transformations. Key Word: Prediction.
This article addresses a dataset on public school expenditures and SAT performance. Key Words: Multiple regression; Omitted variable bias; Partial correlation; Scatterplot.
This article describes a dataset on the readability of booklets about cancer and the reading levels of patients with cancer. Students should be familiar with scales of measurement, data reduction, measuring center, constructing and interpreting displays, and reaching conclusions in real problems. Key Words: Ordinal data, Means, Medians, Histograms
This article presents data for examining the ability of individuals to choose numbers randomly. Three datasets of six-tuples selected by a lottery game, generated by S-Plus, and chosen by college students can be compared using descriptive statistics and goodness of fit tests to explore bias and randomness. Key Words: Boxplots; Chi-squared tests; Minimum gap; QQ plots.
