Assignment Task
Part 1 – Consolidating Concepts
- Describe when you would use an Analysis of Variance, and how it differs from other statistical tests you learned about in Modules 03 and 04, such as z tests, t tests, and chi square tests.
- Compare between group variation and within group variation . Describe how the two relates to the F ratio and what the size of the F ratio means.
- Describe the differences between a one-way ANOVA, one-way repeated measures ANOVA, and two-way mixed ANOVA.
Part 2 – Application Using Statistical Software
Always remember to check for outliers.
Scenario: A researcher is interested in exploring the most effective method for treating rheumatoid arthritis (RA). To study this, they conduct a series of experiments.
First, they randomize 90 patients with RA into one of 3 groups: standard treatment (methotrexate monotherapy; assigned 0), a novel monoclonal antibody treatment (assigned 1), and a combination of both the methotrexate and the monoclonal antibody (assigned 2). Six months later, they asked patients to come back in and measure their C reactive protein (CRP), which is a marker of systemic inflammation and thus disease symptomology in people with RA.
1. Does CRP differ between the three intervention groups? Answer the question using the M05 Homework Data file.
- State your hypothesis statements and significance level.
- Describe the statistical analysis you chose, why you chose that test, and what the grouping factor and levels are.
- Describe the assumptions of this statistical test. Describe how you tested the assumptions and provide any relevant statistical output.
- Use SPSS to conduct the analysis, report your findings including the test statistic and p value. Include pairwise comparisons tests, if applicable.
- State whether you would reject or fail to reject the null hypothesis in this scenario and provide a brief summary of the findings.
Scenario: The researchers also wanted to explore the functional impairments between the groups. The same 90 individuals were asked to complete a questionnaire at the 6-month follow-up. The responses to the questionnaire are coded to give a functional impairment score from 1 to 6 (1 being the least impaired, 6 being the most).
2. Does functional impairment differ between the three intervention groups?
Answer the question using the M05 Homework Data file (Dataset2) in.
- State your hypothesis statements and significance level.
- Describe the statistical analysis you chose, why you chose that test, and what the grouping factor and levels are.
- Describe the assumptions of this statistical test. Describe how you tested the assumptions and provide any relevant statistical output.
- Use SPSS to conduct the analysis, report your findings including the test statistic and p value. Include pairwise comparisons tests, if applicable.
- State whether you would reject or fail to reject the null hypothesis in this scenario.
Scenario: Based on the findings from the first two studies, the researchers decide to conduct a third analysis that explores how clinical markers of RA change over time in the combination therapy group. They took the 30 patients who were randomized into the combination therapy group (ie. Group 2) and collected their CRP at 12 months and 18 months in addition to the data at 6 months from the first analysis.
3. Does CRP change over time?
Answer the question using the M05 Homework Data file (Dataset 3) in.
- State your hypothesis statements and significance level.
- Describe the statistical analysis you chose, why you chose that test, and what the grouping factor and levels are.
- Describe the assumptions of this statistical test. Describe how you tested the assumptions and provide any relevant statistical output.
- Use SPSS to conduct the analysis, report your findings including the test statistic and p value. Include pairwise comparisons tests, if applicable.
- State whether you would reject or fail to reject the null hypothesis in this scenario, provide a brief summary of findings.
