spss computation and interpretation

Using the example from Ottomanelli and colleagues (2012), participants were randomized to receive Supported Employment or treatment as usual. A third group, also a treatment as usual group, consisted of a non-randomized observational group of participants. A simulated subset was selected for this example so that the computations would be small and manageable. The independent variable in this example is treatment group (Supported Employment, Treatment as Usual- Randomized, and Treatment as Usual-Observational/Not Randomized), and the dependent variable was the number of hours worked post-treatment. Supported employment refers to a type of specialized interdisciplinary vocational rehabilitation designed to help people with disabilities obtain and maintain community-based competitive employment in their chosen occupation (Bond, 2004).

These data are presented in HW7.sav. The null hypothesis is: â€œThere is no difference between the treatment groups in post-treatment number of hours worked among veterans with spinal cord injuries.â€

Questions to be answered in word doc –

Open in SPSS. Use the dataset to answer the following questions.

1. Do the data meet criteria for homogeneity of variance? Provide a rationale for your answer.
2. What is the F value, and the numerator and denominator degrees of freedom?
3. Compute the ANOVA using SPSS and paste the SPSS table containing the F into your homework.
4. Is the F significant at a=0.05? Specify how you arrived at your answer.
5. What is the exact likelihood of obtaining our F value at least as extreme or as close to the one that was actually observed, assuming that the null hypothesis is true?
6. Write your interpretation of the results, as you would in an APA-formatted journal.
7. Is there a difference in your final interpretation when comparing the results of the LSD post-hoc test versus Tukey HSD test? Provide a rationale for your answer.
8. If the researcher decided to combine the two Treatment as Usual groups to represent a overall â€œControlâ€ 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? Provide a rationale for your answer.