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CA Foundation · Quantitative Aptitude · Statistical Description of Data

A company in Ahmedabad has 600 employees: 300 in production, 200 in sales and 100 in administration. HR wants a sample of 60 employees such that each department is represented in proportion to its size, with random selection inside each department. Which sampling method and sample allocation (production, sales, administration) is this?

This is stratified random sampling with allocation 30, 20 and 10. Each department is a stratum, and proportional allocation applies the fraction 60/600 = 1/10 to each department size. Equal allocation of 20 each would not be proportional to department size.

  1. ASimple random sampling, 20, 20, 20
  2. BStratified random sampling, 30, 20, 10Correct
  3. CSystematic sampling, 30, 20, 10
  4. DStratified random sampling, 20, 20, 20

Explanation

Departments are strata and random selection is done within each, so it is stratified sampling. Proportional allocation uses the sampling fraction 60/600 = 1/10, giving 30, 20 and 10. Equal allocation of 20 each ignores department sizes, so it is not proportional.

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