Factorial Analysis of Variance Julia Hartman
Transcription
Factorial Analysis of Variance Julia Hartman
An Interactive Tutorial for SPSS 10.0 for Windows© Factorial Analysis of Variance by Julia Hartman Next © Copyright 2000, Julia Hartman 1 Factorial ANOVA: Introduction In this tutorial, Factorial Analysis of Variance (ANOVA) will be used to determine whether gender and residency location interact to affect scores on the US Medical Licensing Exam (Part 2) scores. Next © Copyright 2000, Julia Hartman 2 Factorial ANOVA: Introduction • Independent variables (fixed factors) gender: Gender of student (1 = female, 2 = male) resloc: Residency location (1 = in-state, 2 = out of state) • Dependent variable usmle2: USMLE Step 2 (continuous) Next © Copyright 2000, Julia Hartman 3 Factorial ANOVA: Starting the Procedure • In the menu, click Analyze © Copyright 2000, Julia Hartman 4 Factorial ANOVA: Starting the Procedure • In the menu, click on Analyze • Point to General Linear Model © Copyright 2000, Julia Hartman 5 Factorial ANOVA: Starting the Procedure • In the menu, click on Analyze • Point to General Linear Model • Point to Univariate… © Copyright 2000, Julia Hartman 6 Factorial ANOVA: Starting the Procedure • In the menu, click on Analyze • Point to General Linear Model • Point to Univariate… … and click. © Copyright 2000, Julia Hartman 7 Factorial ANOVA: Selecting Variables Choose the variables for analysis from the list in the variable box. For this tutorial, begin by pointing to the variable labeled GENDER OF STUDENT © Copyright 2000, Julia Hartman 8 Factorial ANOVA: Selecting Variables Choose the variables for analysis from the list in the variable box. For this tutorial, begin by pointing to the variable labeled GENDER OF STUDENT …and click. © Copyright 2000, Julia Hartman 9 Factorial ANOVA: Selecting Variables Move gender, a categorical variable, to the box labeled Fixed Factor(s) by clicking the arrow. © Copyright 2000, Julia Hartman 10 Factorial ANOVA: Selecting Variables Scroll down the list, point to the variable resloc, which is labeled RESIDENCY LOCATION, © Copyright 2000, Julia Hartman 11 Factorial ANOVA: Selecting Variables Scroll down the list, point to the variable resloc, which is labeled RESIDENCY LOCATION, …and click. © Copyright 2000, Julia Hartman 12 Factorial ANOVA: Selecting Variables Move resloc, another categorical variable, to the box labeled Fixed Factor(s) by clicking the arrow. © Copyright 2000, Julia Hartman 13 Factorial ANOVA: Selecting Variables Scroll further down the list and point to the variable usmle2, which is labeled USMLE STEP 2, © Copyright 2000, Julia Hartman 14 Factorial ANOVA: Selecting Variables Scroll further down the list and point to the variable usmle2, which is labeled USMLE STEP 2 TOTAL, …and click. © Copyright 2000, Julia Hartman 15 Factorial ANOVA: Selecting Variables Move usmle2, a continuous variable, to the box labeled Dependent Variable by clicking the arrow. © Copyright 2000, Julia Hartman 16 Factorial ANOVA: Tutorial Options The Univariate GLM procedure offers a number of options. Click this button for a list of the options included in this tutorial. © Copyright 2000, Julia Hartman 17 Factorial ANOVA: List of Tutorial Options Click the box for the desired option. • Profile plots of estimated marginal means • Post hoc tests for pairwise multiple comparisons • Optional descriptive and diagnostic statistics • Continue with the analysis © Copyright 2000, Julia Hartman 18 Factorial ANOVA: List of Tutorial Options Click the box for the desired option. • Profile plots of estimated marginal means • Post hoc tests for pairwise multiple comparisons • Optional descriptive and diagnostic statistics • Continue with the analysis © Copyright 2000, Julia Hartman 19 Factorial ANOVA: List of Tutorial Options Click the box for the desired option. • Profile plots of estimated marginal means • Post hoc tests for pairwise multiple comparisons • Optional descriptive and diagnostic statistics • Continue with the analysis © Copyright 2000, Julia Hartman 20 Factorial ANOVA: List of Tutorial Options Click the box for the desired option. • Profile plots of estimated marginal means • Post hoc tests for pairwise multiple comparisons • Optional descriptive and diagnostic statistics • Continue with the analysis © Copyright 2000, Julia Hartman 21 Factorial ANOVA: Profile Plots Request profile plots of estimated marginal means by clicking the button labeled Plots… © Copyright 2000, Julia Hartman 22 Factorial ANOVA: Profile Plots This tutorial requests both available profile plots, gender*resloc and resloc*gender. Click gender in the Factors box. © Copyright 2000, Julia Hartman 23 Factorial ANOVA: Profile Plots Move gender to the Horizontal Axis box by clicking the arrow. © Copyright 2000, Julia Hartman 24 Factorial ANOVA: Profile Plots Now click resloc in the Factors box … © Copyright 2000, Julia Hartman 25 Factorial ANOVA: Profile Plots and move it to the Separate Lines box by clicking the arrow. © Copyright 2000, Julia Hartman 26 Factorial ANOVA: Profile Plots Click the Add button to request the plot. © Copyright 2000, Julia Hartman 27 Factorial ANOVA: Profile Plots To request the plot of resloc*gender, click resloc in the Factors box. © Copyright 2000, Julia Hartman 28 Factorial ANOVA: Profile Plots Move resloc to the Horizontal Axis box by clicking the arrow. © Copyright 2000, Julia Hartman 29 Factorial ANOVA: Profile Plots Now click gender in the Factors box… © Copyright 2000, Julia Hartman 30 Factorial ANOVA: Profile Plots …and move it to the Separate Lines box by clicking the arrow. © Copyright 2000, Julia Hartman 31 Factorial ANOVA: Profile Plots Click the Add button to request the plot. © Copyright 2000, Julia Hartman 32 Factorial ANOVA: Profile Plots Click the Continue button. © Copyright 2000, Julia Hartman 33 Factorial ANOVA: Post Hoc Multiple Comparisons To request post hoc tests for pairwise multiple comparisons, click the Post Hoc… button. (The factors in this analysis-gender and resloc--each have only two categories, so post hoc option is explained only for tutorial purposes.) © Copyright 2000, Julia Hartman 34 Factorial ANOVA: Post Hoc Multiple Comparisons This example requests tests for gender only. Click gender in the Factor(s) box. © Copyright 2000, Julia Hartman 35 Factorial ANOVA: Post Hoc Multiple Comparisons Move gender to the Post Hoc Tests for: box by clicking the arrow. © Copyright 2000, Julia Hartman 36 Factorial ANOVA: Post Hoc Multiple Comparisons Request multiple comparison test(s) by clicking in the corresponding checkbox. For this tutorial, click Bonferroni. © Copyright 2000, Julia Hartman 37 Factorial ANOVA: Post Hoc Multiple Comparisons In SPSS, you can request as many multiple comparison tests as you want. To continue the tutorial, click the Continue button. © Copyright 2000, Julia Hartman 38 Factorial ANOVA: Optional Descriptive and Diagnostic Statistics To display estimated marginal means, parameter estimates, and descriptive and diagnostic statistics, and or to change the alpha level, click the Options… button. © Copyright 2000, Julia Hartman 39 Factorial ANOVA: Options: Estimated Marginal Means You can request an overall (grand) marginal mean, as well as marginal means for the factors and the interaction(s). To select all of these at once, first click [OVERALL] . © Copyright 2000, Julia Hartman 40 Factorial ANOVA: Options: Estimated Marginal Means Hold the Shift key (on the keyboard) and click gender*resloc to select the entire list. © Copyright 2000, Julia Hartman 41 Factorial ANOVA: Options: Estimated Marginal Means Click the arrow to move the factors and factor interaction terms to the Display Means for: box. © Copyright 2000, Julia Hartman 42 Factorial ANOVA: Options: Estimated Marginal Means In SPSS, you can display information by rightclicking, but rightclicking doesn’t work in this tutorial. To see what right-clicking would show, left-click Compare main effects. © Copyright 2000, Julia Hartman 43 Factorial ANOVA: Options: Estimated Marginal Means Click the checkbox for Compare main effects. © Copyright 2000, Julia Hartman 44 Factorial ANOVA: Options: Estimated Marginal Means You can change the method used for confidence interval adjustments by selecting from the drop-down list. Click the drop-down arrow for Confidence interval adjustment. © Copyright 2000, Julia Hartman 45 Factorial ANOVA: Options: Estimated Marginal Means This tutorial will use the default method, so click elsewhere on the window to close the drop-down menu. © Copyright 2000, Julia Hartman 46 Factorial ANOVA: Selecting Options Request other options by clicking the appropriate checkbox. In the Display area, click the checkbox for Descriptive statistics… © Copyright 2000, Julia Hartman 47 Factorial ANOVA: Selecting Options …and the one for Homogeneity tests. © Copyright 2000, Julia Hartman 48 Factorial ANOVA: Selecting Options This tutorial uses no more options, so click the Continue button. © Copyright 2000, Julia Hartman 49 Factorial ANOVA: Run the analysis Click the OK button to run the Factorial ANOVA. © Copyright 2000, Julia Hartman 50 Factorial ANOVA Output: Warnings and General Information The labels and format of your output may be somewhat different. Next © Copyright 2000, Julia Hartman 51 Factorial ANOVA Output: : Descriptive Statistics Previous © Copyright 2000, Julia Hartman Next 52 Factorial ANOVA Output: Test of Equality of Error Variances Previous © Copyright 2000, Julia Hartman Next 53 Factorial ANOVA Output: Tests of Between-Subjects Effects Previous © Copyright 2000, Julia Hartman Next 54 Factorial ANOVA Output: Estimated Marginal Means: Grand Mean Previous © Copyright 2000, Julia Hartman Next 55 Factorial ANOVA: Gender: Estimated Marginal Means Previous © Copyright 2000, Julia Hartman Next 56 Factorial ANOVA: Gender: Pairwise Comparisons Previous © Copyright 2000, Julia Hartman Next 57 Factorial ANOVA: Gender: Univariate Tests Previous © Copyright 2000, Julia Hartman Next 58 Factorial ANOVA: Resloc: Estimated Marginal Means Previous © Copyright 2000, Julia Hartman Next 59 Factorial ANOVA: Resloc: Pairwise Comparisons Previous © Copyright 2000, Julia Hartman Next 60 Factorial ANOVA: Resloc: Univariate Tests Previous © Copyright 2000, Julia Hartman Next 61 Factorial ANOVA: Interaction: Means, Std Errors, C.I. Previous © Copyright 2000, Julia Hartman Next 62 Factorial ANOVA: Profile Plot: Gender*Resloc Previous © Copyright 2000, Julia Hartman Next 63 Factorial ANOVA: Profile Plot: Resloc*Gender Previous © Copyright 2000, Julia Hartman Next 64 An Interactive Tutorial for SPSS 10.0 for Windows©: Factorial ANOVA Click one of the following: • Repeat this tutorial • Return to the list of options in this tutorial • Return to the list of tutorials © Copyright 2000, Julia Hartman 65