Overview
PH 627: Advanced Statistical Methods in Public Health
M5 Assignment 1. A study was undertaken to measure and compare sexist attitudes of students at various types of colleges. Random samples of 10 undergrad seniors of each sex were selected from each of three types of colleges. A questionnaire was then administered to each student, from which a score for “degree of sexism”—defined as the extent to which a student considered males and females to have different life roles—was determined (the higher the score, the more sexist the attitude). The resulting data are given in the following table. College Type Male Female Coed with 75% or more males 50, 35, 37, 32, 46, 38, 36, 40, 38, 41 38, 27, 34, 30, 22, 32, 26, 24, 31, 33 Coed with less than 75% males 30, 29, 31, 27, 22, 20, 31, 22, 25, 30 28, 31, 28, 26, 20, 24, 31, 24, 31, 26 Not coed 45, 40, 32, 31, 26, 28, 39, 27, 37, 35 40, 35, 32, 29, 24, 26, 36, 25, 35, 35 a. Plot the cell means by college type for males and females. b. Use SAS to calculate the F statistics corresponding to a model with both factors fixed. c. Discuss the analysis of the data for this fixed-effects model case. 2. A crime victimization study was undertaken in a medium-sized southern city. The main purpose was to determine the effects of being a crime victim on confidence in the law enforcement authority and in the legal system itself. A questionnaire was administered to a stratified random sample of 40 city residents; among the information elicited were data on the number of times victimized, a measure of social class status, and a measure of the respondent’s confidence in law enforcement and in the legal system. The data are produced in the following table. Number of times Victimized Social Class Status LO MED HI 0 4, 14, 15, 19, 17, 17, 16 7, 10, 12, 15, 16 8, 19, 10, 17 1 2, 7, 18 6, 19, 12, 12 7, 6, 5, 3, 16 2+ 7, 8, 2, 11, 12 1, 2, 4 4, 2, 8, 9 a. Plot the cell means by number of times victimized and social class status. b. Use SAS to calculate the F statistics corresponding to a model with both factors fixed. c. Discuss the analysis of the data for this fixed-effects model case.