The dataset described in this article contains data on retired Major League Baseball players, eligible for the MLB Hall of Fame. The data can be used to illustrate descriptive statistical methods (numerical, graphical, and tabular) or inferential statistics (hypothesis testing, confidence intervals, etc.). The data is in .dat format.
As described in the web page itself: "This document was prepared as an illustration of the use of both t tests and correlation/regression analysis in drawing conclusions from data in an actual study." The study compares athletic performance of swimmers that are optimists vs. pessimists.
This page contains applets and data files that supplement the text "Investigating Statistical Concepts, Applications, And Methods." The applets and files are organized according to chapter; each data file is available in Minitab or text format.