# Variable Validity, Reliability, Bias

• ### Calculator Instructions for Elementary Statistics

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.
• ### The First shall be Last

This article provides the example of student form orders to demonstrate the unreliability of combining data from two different distributions (or subjects).
• ### STATISTICAL LITERACY: READING TABLES OF RATES AND PERCENTAGES

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.
• ### Probability, Genetics and the Human Condition

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.
• ### Data Collection: U.S. Retail Gasoline Prices

This Department of Energy website provides weekly average gasoline prices for several regions, states and cities. The averages are produced from a weekly survey of around 800 retail gasoline stations. The site includes information on data collection methods, survey methodology and historical data.
• ### Dataset Example: Trying To Be Random in Selecting Numbers for Lotto

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.
• ### Dataset Example: Readability of Educational Materials for Patients with Cancer

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
• ### Getting What You Pay For: The Debate Over Equity in Public School Expenditures

This article addresses a dataset on public school expenditures and SAT performance. Key Words: Multiple regression; Omitted variable bias; Partial correlation; Scatterplot.
• ### Dataset Example: Televisions, Physicians, and Life Expectancy

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.
• ### Can a difference be important if it is not significant?

This short article discusses the difference between "important" and "statistically significant." The data used come from a study comparing male faculty salaries to female faculty salaries.