This case describes the situation faced by the general manager of the A's at the end of the 1980 baseball season. The A's star pitcher, in negotiating his contract, claims that attendance was noticeably higher at games in which he was the starting pitcher. Game-by-game data for the 1980 season on home attendance and 10 variables affecting attendance are given. The case is suited for use near the end of a module on regression. It can be used to (1) review the t-test for a difference in means and relate the difference to regression with a dummy variable, (2) illustrate the importance of a model-building framework, even if used to evaluate someone else's models, (3) illustrate the use of dummy variables, and (4) point out the difference between conditional and marginal inference.
A student spreadsheet is available.
The supplement to the A case, QA-0313, contains the results of several regression analyses of the A's 1980 home-attendance data and may be used with the A case to facilitate analysis of the situation. (The B case is QA-0283.)