Homework 3
Use the
SOCR Neuroimaging dataset of visceral pain, irritable bowel syndrome, ulcerative colitis,
and Crohn's disease.
- Problem 1: Investigate the effect of the grouping (Group), separating the 3 cohorts, on the
gray matter brain volume (GMV), i.e., you can take group as a categorical variable and the
GMV values as the observations. Use the
SOCR 1-Way ANOVA applet, or
R to carry the
calculations. Provide all results and explicitly state your inference.
- Problem 2: Use
2-way ANOVA (using gender and group as the 2 factors) on the
R_insular_cortex volume (insular shape has been reported to be associated with visceral pain, irritable bowel syndrome,
and ulcerative colitis). Repeat the analysis using the counterlateral L_insular_cortex volume.
Report your findings and interpret the results.
- Problem 3: Determine a
linear model of association between the the response (Total Brain Volume, TBV)
and the following predictors (Group, Sex, and Age). Explain your findings and interpret
your model results.
- Problem 4: Do people with larger brains necessarily have bigger
hippocampal volumes (e.g., L_hippocampus + R_hippocampus)? Formulate a research hypothesis,
propose an appropriate statistical technique, apply the corresponding software tool, and
report your findings.
