Calculating Analysis of Variance (ANOVA)

EXERCISE 33
Calculating Analysis of Variance (ANOVA) and Post Hoc Analyses Following ANOVA

  1. Do the data meet criteria for homogeneity of variance? Provide a rationale for your answer.

 

  1. If calculating by hand, draw the frequency distribution of the dependent variable, hours worked. What is the shape of the distribution? If using SPSS, what is the result of the Shapiro-Wilk test of normality for the dependent variable?

 

  1. What are the means for three groups’ hours worked on a job?

 

  1. What are the F value and the group and error df for this set of data?

 

  1. Is the F significant at α = 0.05? Specify how you arrived at your answer.

 

  1. If using SPSS, what is the exact likelihood of obtaining an F value at least as extreme as or as close to the one that was actually observed, assuming that the null hypothesis is true?

 

  1. Which group worked the most weekly job hours post-treatment? Proved a rationale for your answer.

 

  1. Write your interpretation of the results as you would in an APA-formatted journal.

 

  1. Is there a difference in your final interpretation when comparing the results of the LSD post hoc test versus Tukey HSD test?

 

  1. If the researcher decided to combine the two Treatment as Usual groups to represent an overall “Control” group, then there would be two groups to compare: Supported Employment versus Control. What would be the appropriate statistic to address the dif­ference in hours worked between the two groups?