Stratified

Question 1

In this method, the population is first divided into subgroups (or strata) who all share a similar characteristic.

Answer 1

Stratified sampling

Question 2

It is used when we might reasonably expect the measurement of interest to vary between the different subgroups, and we want to ensure representation from all the subgroups.

Answer 2

Stratified sampling

Question 3

You are surveying academic performance of students in a school. Generally, the population is 2,000 students. You produce a list of all their names, organized in alphabetical order to eliminate any patterns and decide that 10% of the entire population (200 students) is a representative sample size. To determine the sampling interval, you divide 2,000 by 200 for a quotient of 10. Then you use a random number generator to decide on a starting point of eight. Thus, starting with the eighth student on the list, you send a survey to every tenth student.

Answer 3

Stratified sampling