市场调查方法(英文版)第十五章.ppt

Chapter 15Differences Between Groups and Relationships Among Variables LEARNING OUTCOMES Understand what multivariate statistical analysis involves and know the two types of multivariate analysis Interpret results from multiple regression analysis. Interpret results from multivariate analysis of variance (MANOVA) Interpret basic exploratory factor analysis results What Is the Appropriate Test of Difference? Test of Differences An investigation of a hypothesis that two (or more) groups differ with respect to measures on a variable. Behavior, characteristics, beliefs, opinions, emotions, or attitudes Bivariate Tests of Differences Involve only two variables: a variable that acts like a dependent variable and a variable that acts as a classification variable. Differences in mean scores between groups or in comparing how two groups’ scores are distributed across possible response categories. EXHIBIT 15.1 Choosing the Right Statistic EXHIBIT 15.1 Choosing the Right Statistic (cont’d) Common Bivariate Tests Cross-Tabulation Tables: The χ2 Test for Goodness-of-Fit Cross-Tabulation (Contingency) Table A joint frequency distribution of observations on two more variables. χ2 Distribution Provides a means for testing the statistical significance of a contingency table. Involves comparing observed frequencies (Oi) with expected frequencies (Ei) in each cell of the table. Captures the goodness- (or closeness-) of-fit of the observed distribution with the expected distribution. Example: Papa John’s Restaurants Chi-Square Test Degrees of Freedom (d.f.) The t-Test for Comparing Two Means Independent Samples t-Test A test for hypotheses stating that the mean scores for some interval- or ratio-scaled variable grouped based on some less than interval classificatory variable. The t-Test for Comparing Two Means (cont’d) Determining when an independent samples t-test is appropriate: Is the dependent variable interval or ratio? Can the dependent variable scores be grouped based upon som