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€
Download the file: see attached file
Questions to be answered in word doc –
Open in SPSS. Use the dataset to answer the following questions.
- Do the data meet criteria for homogeneity of variance? Provide a rationale for your answer.
- What is the F value, and the numerator and denominator degrees of freedom?
- Compute the ANOVA using SPSS and paste the SPSS table containing the F into your homework.
- Is the F significant at a=0.05? Specify how you arrived at your answer.
- 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?
- Write your interpretation of the results, as you would in an APA-formatted journal.
- 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.
- 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.