Question

dr g is trying to garner opinions on students grc experience. he surveys 120 students at random from freshmen, sophomore, junior, and senior classes - thus covering all student groups and each and every class was sampled: 30 were freshmen, 30 sophomore, 30 junior and 30 senior. the sampling technique used is: a. simple random sampling. b. stratified random sampling c. multistage sampling. d. none fo the above

Explanation:

Stratified random sampling involves dividing the population into subgroups (strata) and then randomly sampling from each stratum. Here, the population (students) is divided into strata (freshmen, sophomore, junior, senior) and a random sample of 30 is taken from each stratum. Simple random sampling would involve randomly selecting 120 students without dividing into groups. Multistage sampling would involve multiple levels of sampling (e.g., first select classes, then students within classes).

Answer:

B. stratified random sampling