Problem
a) You are recruiting participants for a study. In 2 sentences, explain the difference between random sampling and purposeful sampling in this part of a research study.
b) A group of investigators are interested in understanding the causal relationship between a specific exposure and a rare disease, in this case, the rare disease is early-onset Alzheimer's (occurs between ages 30-60). Based on this, would you recommend a case-control or prospective cohort study design? Justify your rationale for choosing one over the other.
c) In a few sentences, explain the difference between random selection and randomization.