CA Foundation · Quantitative Aptitude · Statistical Description of Data
A researcher in Jaipur divides a city's 1,000 retailers into three groups according to turnover (small, medium, large). Within each group, she picks retailers using a random number table in proportion to group size. This sampling method is:
This is stratified random sampling, because the population is first divided into strata by turnover and then random samples are drawn from each stratum in proportion to its size. Simple random sampling would not divide the population into groups first.
- ASimple random sampling
- BSystematic sampling
- CStratified random samplingCorrect
- DCluster sampling
Explanation
The population is split into homogeneous groups (strata) by turnover and a random sample is drawn from each, proportional to size. That is stratified random sampling. Simple random sampling would draw from the whole list without grouping, so it is wrong.
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