Cluster sampling is used when

AThe population is scattered and the sample size is to be kept large

BThe population is fully homogeneous

CA long survey is needed over a wide area

DBoth the population is scattered with a large sample and a long, wide survey is needed ✓ Correct

Correct answer: (D) Both the population is scattered with a large sample and a long, wide survey is needed

Explanation

Cluster sampling is chosen when the population is scattered with a large sample and a long, wide-area survey is needed.

The option limited to a scattered population and a large sample states only one part of the condition.

A fully homogeneous population actually favours a small simple random sample, not clustering.

The option limited to a long survey over a wide area again captures only part of the need.

Clustering divides the population into natural groups and samples whole clusters to cut cost and travel.

It trades some precision for economy when the population spreads across a broad territory.

Want more like this? Create a free account to practise a full test, track your progress, and get spaced-repetition review.