The difference between the upper limit and the lower limit of a class interval is called: MCQ with Answer and Explanation

Explanation:
Perinatal mortality reflects the quality of antenatal care, skilled attendance at birth, and immediate newborn care, making it a sensitive measure for evaluating maternal-child health programs.

Explanation:
Fisher's index = √(120 × 110) = √13200 ≈ 114.89 ≈ 114.9. This geometric mean balances the upward bias of Laspeyres and downward bias of Paasche.

Explanation:
Mean requires precise midpoints for all classes. Open-end classes lack boundaries, making precise mean calculation impossible.