Which of the following samples are non-random or non-probability samples?

(A) Systematic sample

(B) Quota sample

(C) Cluster or area sample

(D) Purposive sample

(E) Replicated sample

Choose the correct answer from the options given below: 

The correct answer is  (B), (D) Only.

Key PointsLet's analyze each option:

• Option 1: (A), (C) Only
  • This statement is incorrect because both Systematic samples (A) and Cluster or area samples (C) are types of probability sampling techniques.
  • Systematic sampling involves selecting elements from an ordered sampling frame, and each element has an equal probability of being chosen.
  • Cluster sampling involves dividing the population into clusters and then randomly selecting entire clusters, ensuring randomness.
• Option 2: (B), (C), (D) Only
  • This statement is incorrect because Cluster or area sample (C) is not a non-probability sampling technique; it's a probability sampling method.
  • Quota sample (B) and Purposive sample (D) are indeed non-probability samples, but including Cluster sample (C) makes this option partially incorrect.
• Option 3: (A), (D), (E) Only
  • This statement is incorrect because Systematic sample (A) and Replicated sample (E) are not non-probability sampling techniques.
  • Systematic samples (A) involve randomness and structured selection, suitable for probability sampling.
  • Replicated samples (E) generally refer to repeated sampling methods aimed at validating results, having elements of randomness.
  • Purposive sample (D), however, is a non-probability sample.
• Option 4: (B), (D) Only
  • This statement is correct because both Quota sample (B) and Purposive sample (D) are non-probability sampling techniques.
  • Quota sampling involves selecting samples based on pre-set quotas, without random selection factors.
  • Purposive sampling involves selecting samples deliberately for specific purposes, relying on the judgment of the researcher.
  • Quota and purposive samples are often used in qualitative research for detailed, targeted insights rather than random representation.