2 Way ANOVA, Post Hoc Tests

The data set for this exercise is: 2WayAnovaR.sav

  1. Are each of the three variables of interest continuous or categorical?
  2. Of attitude and peer pressure, which is the stronger predictor of intention?
  3. What is the median for attitudes and the median for peer pressure?

4a.  Look at the post hoc menu options. Should you check anything here? Why or why not?

4b.  Is each main effect significant? Is the interaction significant?

4c.  Write a paragraph reporting on the results of this analysis, use proper APA style (don’t forget to include effect size and, for significant findings, the means).

  1. Add a sentence or two to your paragraph from #4c  indicating that:  “A ______ post-hoc test revealed that ……” (describe outcome, e.g,. are all four means different from one another?).

ANCOVA

The data set for this exercise is: ANCOVA.sav

This experiment measured the extent to which the female participants base their self-esteem on the reflected appraisals of other people (10 item scale, each item labeled r1, r2, etc.), and measured participants’ trait self-esteem (rosen). Next, either positive or negative feedback was given to the participant. Last, researchers measured temporary state self-esteem related to their feelings about how they looked (appse).

6a. Write down which item numbers you recoded.

6b. Write a sentence reporting whether the reliability of the scale is adequate or not (report the alpha).

    7.  Test the hypothesis that negative feedback leads to lower state self-esteem (appse) and write an APA style paragraph reporting your conclusions.

    8a.  In the 2-way analysis, does feedback have any impact on state self-esteem? 

    8b.  Why were you unable to see the influence of feedback on state self-esteem in the analysis from #7? (Hint: comment on the informative nature of interactions.)

9a.  Confirm or disconfirm this with a bivariate correlation (include the correlation in APA style with your response).

9b.  Assuming rosen is correlated with appse, why should we probably do an ANCOVA rather than making rosen the third variable in a 2 x 2 x 2 ANOVA? (Hint: this is a conceptual, not statistical question)

10.  Write a paragraph explaining the analysis and results. The following should be the first sentence of your paragraph: “We conducted a 2 (hi/low reflected appraisals) x 2 (positive/negative feedback) ANCOVA with trait self-esteem as the covariate.” Report on whether trait self-esteem “was a significant covariate” (or not) first.  Then report on the main effects and then interactions including all the proper information in APA style.