# Graphical Displays

• ### Smiles and Leniency

This case study addresses the question: "Will a smiling person accused of a crime be treated more leniently than one who is not smiling? If so, does the type of smile make a difference?" It concerns the following concepts: quantile/boxplots, contrasts among means, Dunnett's test, and Bonferroni correction.
• ### Instructor Reputation and Teacher Ratings

This case study covers the concepts including: boxplots, stem and leaf displays, two-sample t tests, and analysis of variance. It also assesses the question, "Does an instructor's reputation affect ratings of the instructor's lecture?"
• ### Who is Buying iMacs?

This case study covers the following concepts: confidence intervals for proportions and the normal approximation to the binomial. It also assesses the question: "What proportion of the iMac purchasers are new computer owners?"
• ### Natural Language Interface

This case study assesses the question, "Is it easier to learn to use computer software that uses natural language commands?" Concepts: analysis of covariance, adjusted means, boxplots
• ### Physicians' Reactions to Overweight Patients

This case study assesses the question, "Do physicians discriminate against overweight patients?" This study indicates that, at least in one respect, they do. Concepts: t-test, means, boxplots
• ### Against All Odds: 26. Case Study

This free online video program "presents a detailed case study of statistics at work. Operating in a real-world setting, the program traces the practice of statistics - planning the data collection, collecting and picturing the data, drawing inferences from the data, and deciding how confident we can be about our conclusions. Students will begin to see the full range and power of the concepts and techniques they have learned." This individual video is accessed by scrolling down to the "Individual Program Descriptions - 26. Case Study " and click the "VOD" icon at the top-right of the description.
• ### DAU StatRefresher: Basic Probability

This interactive tutorial on Basic Probability helps students understand the basic concepts of probability, define independent and compound events, use the basic properties of probability, understand the concept of conditional probability, and solve exercise problems using basic probability.
• ### DAU StatRefresher: Random Variables

This tutorial on Random Variables helps students understand the definition of random variables, recognize and use discrete random variables, recognize and use continuous random variables, and solve exercise problems using random variables.
• ### DAU StatRefresher: Expectations

This interactive tutorial on Expectations helps students understand the concept of expectations, recognize and use variance and standard deviation, understand the method of moments, recognize and use co-variance, and solve exercise problems using expectations.
• ### DAU StatRefresher: Linear Regression

This interactive tutorial on Linear Regression helps the user understand the definition of linear regression, understand the meaning of correlation, use scatter plots, recognize and calculate errors in linear regression, use simple linear regression analysis, use residual analysis of the regression equation, understand the significance of the correlation coefficient and the regression coefficient in linear regression, and solve exercise problems using linear regression.