Question 7 • VA-Probability and Statistics
A stratified random sample divides the population into relevant groups, then randomly selects members from every group. Here, the instrument types are the strata, and choosing 2 students at random from each type includes opinions across the band. Selecting 30 students from the whole band is a simple random sample, while surveying one alphabet group or one year leaves out the other groups.
AI-written and checked against the verified answer.