A technique used when selecting clusters of different sizes is called:

A technique used when selecting clusters of different sizes is called: (a) Cluster sampling

(b) One-stage sampling

(c) Two-stage sampling

(d) Probability proportional to size (PPS)

✅ Correct option: (d) Probability proportional to size (PPS)

Explanation:

Probability Proportional to Size (PPS) sampling is used when clusters vary in size. Larger clusters have a higher probability of selection than smaller ones, ensuring fairness and representativeness. This method prevents bias that may occur if all clusters were given equal selection chances regardless of size. Therefore, PPS is essential in large-scale surveys.

10 Related PPSC Facts:

Used for unequal clusters Larger clusters selected more often Improves representativeness Common in national surveys Reduces sampling bias Requires size measures Used in two-stage sampling Efficient cluster selection Applied in census surveys Enhances precision