PSY 870: Module 4 Problem Set 2 3 Between-Subjects Factorial ANOVA: Study Environments by Gender 1. A. What are the two independent variables in this study? Environment Gender B. What is the dependent variable? 2. The GPA scores Why is a two-way between-subjects factorial ANOVA the correct statistic to use for this research design? 3. Did you find any errors that the researcher made when setting up the SPSS data file ? 4. The reason why that a two-way ANOVA is correct method for the subjects is that it informs whether the effect of one of the independent variables on the dependent variable is the same for all values of the other independent variable. For instance, if gender (male or female) has certain influenced on study's environment. No 4. Run Descriptive Statistics on the dependent variable data. What do the skewness is .652 Kurtosis is -.063 What values tell you about whether the data satisfy the assumption of normality? For instance, of the values is testing for normality. Therefore, many statistics inferences require that a distribution be normal or nearly normal. For example, a normal distribution has skewness and excess kurtosis of 0. As a result, the distribution is not close to those values then it is not probably close to normal. 5. Perform a between-subjects factorial ANOVA on the data. Between-Subjects Factors Value Label Environment N 1 Front of TV 80 2 Library 80 3 Food Court 80 1 120 Gender 2 Male Female 120 b. What do the results of the Tests of Between-Subjects Effects tell you? Was there a significant main effect of Environment on GPA improvement? no Was there a significant main effect of Sex on GPA improvement? Yes no Was there a significant interaction effect of Environment X Sex on GPA improvement? Yes Squared is .515 /.505 What is the eta squared (2) value associated with that outcome? a. Environment : b. Sex c. : 14.677/6.696 =2.2 14.677/.081 =181.1 01 ~ small d. .06 ~ medium e. .14 ~ large Write-up of the results for the Two-Way Between-Subjects ANOVA This study investigates whether study environment affects academic performance. First, the study used sex of student "moderates" the effect of study environment on academic performance that is, do males and females differ in how much benefit they get from studying in certain environments. Secondly, during the first half of the spring semester, 120 male students and 120 female students in grade 10 at a public high school in a large metropolitan area in the southwestern region of the United States were randomly assigned to one of three study environment: study in front of the TV, at the library, or in the food court. The students could ONLY study in the environment to which they were assigned during the research period. At the end of the 7-week research period, mid-term GPA was computed for each student. A change score was computed for each student: each student's spring midterm GPA was subtracted from his or her GPA for the preceding fall semester. The difference was each student's GPA Improvement score. The GPA improvement score was used to measure academic performance. The ANOVA showed no significant main effect of sex, F (2.651), (.081) mean square and significant, F (.105), p < . 001