## Volume 4, Number 3 (November 1996) ISSN: 1069-1898

## Barbara L. Grabowski and William L. Harkness, "Enhancing Statistics Education With Expert Systems: More Than an Advisory System" (68K)

This article reports on the results of two studies that investigated the effectiveness of different uses of expert systems in large introductory statistics classes. Three groups of students were compared -- those who used an expert system created by the instructor of the course, those who created their own expert system, and those who did not use any at all. The first experiment showed non-significant, but interesting, trends that were explored in the second experiment. In the second experiment, significant differences emerged as the semester evolved in favor of those who used the expert system, regardless of whether or not the students created it themselves. These differences disappeared on the final exam, when technological problems added to the end-of-the-semester tension. These findings support the notion that the use of expert systems in the classroom can have an important impact on the level and amount of learning that occurs. This article describes these two studies in detail and draws some implications for teaching. --BLG

Key Words:Active learning; Computers as thinking tools; Learning with technology.

## G. Steven Rhiel and Wilkie W. Chaffin, "An Investigation of the Large-Sample/ Small-Sample Approach to the One-Sample Test for a Mean (Sigma Unknown)" (58K)

In this article we investigate the large-sample/ small-sample approach to the one-sample test for a mean when the variance is unknown, using the probability of a Type I error as the criterion of interest. We show that in most cases using a t-test (t critical value) provides a more robust test than does using the z-test (standard normal critical value). The only case in which z has some advantage is when using a small sample from a parent population with extremely high kurtosis or with skewness in the direction of the rejection region tail. The implications for teaching the large-sample/small-sample approach in introductory statistics classes are discussed in light of these findings. --GSR

Key Words:Sample size; t critical value; t test statistic; z critical value.

## Hardeo Sahai, Anwer Khurshid, and Satish Chandra Misra, "A Second Bibliography on the Teaching of Probability and Statistics" (35K)

This article presents an extensive collection of references on the teaching of probability and statistics. The bibliography includes articles published in statistical and subject-matter journals and in conference proceedings. --HS

Key Words:Learning; Literature on teaching statistics.

## Joe H. Ward, Jr., and Robert L. Fountain, "More Problem Solving Power: Exploiting Prediction Models and Statistical Software in a One-Semester Course" (74K)

Many widely-adopted college textbooks that are designed for a student's first (and possibly last) statistics course have incorporated new trends in statistical education, but are organized in a manner that is still driven by a traditional computational, rather than a conceptual, framework. An alternative approach allows for the treatment of many seemingly-unrelated conventional procedures such as one- and two-sample t-tests and analyses of variance and covariance under a unifying prediction model approach. Furthermore, this approach, combined with the power of modern statistical software packages, prepares the student to solve problems beyond the scope of traditional procedures. Students will appreciate the acquisition of practical research capabilities and might even be stimulated to continue their study of statistics. --JHW

Key Words:Linear models; Undergraduate teaching techniques.

## "Teaching Bits: A Resource for Teachers of Statistics" (30K)

This column features "bits" of information sampled from a variety of sources that may be of interest to teachers of statistics. Joan Garfield abstracts information from the literature on teaching and learning statistics, while Bill Peterson and Laurie Snell summarize articles from the news and other media that may be used with students to provoke discussions or serve as a basis for classroom activities or student projects. --JG

## Singfat Chu, "Diamond Ring Pricing Using Linear Regression" (11K)

Data presented in a newspaper advertisement suggest the use of simple linear regression to relate the prices of diamond rings to the weights of their diamond stones. The intercept of the resulting regression line is negative and significantly different from zero. This finding raises questions about an assumed pricing mechanism and motivates consideration of remedial actions. --SC

Key Words:Extrapolation; Interpretation of intercept; Model-building; Transformations.Editorial Board for Volume 4, Number 3

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