ANOVA

A psychologist wants to determine whether having a job interferes with student academic performance. She measures academic performance as a grade point average (GPA) on a 4.0 scale, where higher scores indicate better performance. She selects a sample of 30 students - 10 who did not work, 10 who worked part-time, and 10 who worked full-time during the previous semester - and records their GPA. Conduct this analysis using an alpha of .05. 1. What is the IV? Levels of the IV? Level of Measurement of the IV? 2. What is the DV? Level of measurement of the DV? 3. How are subjects assigned to groups? 4. Based on your answers to items 1 - 3, what is the correct hypothesis test for analyzing this data? 5. Define your variables #Enter code

6. Join the vectors into a data frame #Enter code

## noWork partTime fullTime ## 1 3.4 3.5 2.9 ## 2 3.2 3.6 3.0 ## 3 3.0 2.7 2.6 ## 4 3.0 3.5 3.3 ## 5 3.5 3.8 3.7 ## 6 3.8 2.9 2.7 ## 7 3.6 3.4 2.4 ## 8 4.0 3.2 2.5 ## 9 3.9 3.3 3.3 ## 10 2.9 3.1 3.4

7. What is the shape of your data frame - wide or long? 8. Reshape your data into the long format #Enter code here 9. Convert your IV into a fator #Enter code here 10.Make a summary table of the n, mean, and standard deviation of each level of the IV #Enter code here 11. Conduct your ANOVA #Enter code here 12. View the summary of the ANOVA #Enter code here 13. Do we need to conduct post hocs? Explain. 14. Conduct a Tukey HSD #Enter code here 15. Interpret the post hocs 16. Visualize the 95% CI #Enter code here 17. Interpret the confidence interval plot. 18. Summarize your results in APA format. Extra Credit: Make an error bar graph for this data. #Enter code here