Frederick Wiseman

METHODOLOGICAL BIAS IN PUBLIC OPINION SURVEYS

Statistically designed sample surveys have enabled pollsters to gauge public opinion on a wide range of issues. In such surveys, selection of a data collection technique is generally based on four criteria: (1) cost; (2) completion time; (3) response rate; and (4) response bias. Typically, more weight is placed on the first three factors and, as a result, adequate attention has not been given to the latter consideration. The study described in this paper looks at one type of response bias-that which results from the use of a specific data collection method. More specifically, this research uses a controlled experimental design in order to determine whether responses given in a public opinion polling are influenced by the method used to collect the data. Three methods are investigated: (1) mail questionnaire; (2) telephone interview; and (3) personal interview.

Comprehensive Analysis of Golf Performance on the Pga Tour: 1990–2004

Researchers have investigated the relationship between different shot-making measures and performance on the PGA Tour. Prior studies have typically focused on a short period of time or used a restricted sample so long-term trends were not discernible. To remedy this situation, the present study looked at the longitudinal performance of professional golfers from 1990–2004. The findings indicated a remarkable stability in terms of the relative importance of Greens In Regulation and Putting Average in explaining the variability in Scoring Average. The findings also indicated a declining importance of driving in recent years due, in part, to a strengthening of the negative relationship between Driving Distance and Driving Accuracy.

Studying improved performance in golf

The topic of improved performances by athletes in both team and individual sports has shown that each sport has its own unique set of characteristics and these have to be analysed accordingly. This paper presents an extensive analysis of the nature and extent of improvement in golf by analysing the performances of the top players in the Masters tournament throughout the entire history of the event. The results indicate that golfers are obtaining lower scores over time and that the variation of the scores has declined. Further, the distributions of scores are symmetric and display a monotonic reduction of peakedness (kurtosis). These findings are indicative of rapid and improved performance and increased competition.

Use of Regression Diagnostics in Political Science Research

In a regression analysis there may be certain data points (which may or may not be outliers) that are influential in the sense that their presence or absence significantly influences the obtained values of the estimated regression coefficients. The nature of these effects needs to be analyzed in order to determine which, if any, data points should be removed from the data set in order to improve coefficient estimates. A relatively new technique for identifying influential data points is called regression diagnostics. In this presentation, the technique is discussed and its potential usefulness demonstrated by an application on a data set previously analyzed by Tufte (1974).

Major League Baseball Player Salaries: Bringing Realism into Introductory Statistics Courses

Abstract A dataset consisting of salaries of major league baseball players is published at the start of each season in USA Today, and is also made available on the Internet. It is argued that such an easily available dataset and those similar to it can be successfully used by students in a first statistics course for an interesting introduction to data analysis through summary measures and graphical displays. Such an approach is most natural for many students because of a strong interest in sports and economics. Other statistical ideas can be explored as a natural consequence of the discussions that ensue from such an analysis.

An alternative approach to discriminating multivariate populations and its applications to marketing research

A new method for discriminating among multivariate populations, called the Hausdorff procedure, is introduced to the marketing literature. Rules for classification are defined and a limited simulation study is conducted. For the simulation, both the level of collinearity among the discriminating variables and the level of overlap among the populations are varied. The results indicate that this new procedure is particularly suitable when there is either a high degree of collinearity among the predictor variables or considerable overlap of the populations being investigated. The Hausdorff procedure is also applied to two sets of consumer data. In each instance, it is found to be superior to linear discriminant analysis with respect to the percentage of correct classifications.