Describes an expert system microcomputer-based program, ZEERA, which is designed to help users understand and perform statistical analyses. Computer-assisted instruction and the traditional approach of drill and practice are discussed, and benefits of using ZEERA are described based on testing in a university elementary statistics course. (11…

Criticizes the statistical methods used in a previously published article that compared a commercially produced computer program with traditional teaching methods. Measures of instructional effectiveness are described, the assignment of student pairs is examined, and the use of blocking variables with analysis of variance is discussed. (LRW)