ANOVA (analysis of variance) allows the comparison of means when you have more than two groups. For example, we may decide to determine if the means of the number of hours of watching television vary by marital status. Like the t-test, you need to make sure that your dependent variable is continuous. The SPSS eTutor will use the One-Way Between-Groups ANOVA with Post-Hoc Tests to examine the difference in mean of the number of hours of television watched by those who are married, widowed, divorces, or never married.
Click Analyze, Compare Means, then One-way ANOVA. Highlight your dependent (continuous) variable TVhours and move it into the Dependent List box. Then move your independent variable Marital into the Factor box. Your screen should look like this:
Then click the Options box. Click on Descriptive. For Missing values, make sure that you have clicked Exclude cases analysis by analysis. Continue. Your screen should look like this:
Then click on Post Hoc, and Tukey. Click Continue and then OK. Your output will look like this:
How to interpret your output
The descriptives gives you information about each marital status. First check to see if there is signficant difference in the means of the groups. Go to the ANOVA box and cCheck the column Sig. if this number is less than or equal to .05, there is significant difference among the groups. The value for our example is .000 (less than .05). So we do know that there is significant differences of means between our marital groups. If there was not a significant difference, we would stop here. Since we do have a significant difference, go to the Multiple comparisons box next. This is where you will see exactly where the differences occur (these are marked by an *). Note that there are signficant differences between those who are Widowed/Married, Widowed/Divorced, Widowed/Never Married, and Married/Divorce.
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SPSS eTutor by Dee Britton is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.