Splitting Classes for Unequal Intervals

When we use unequal class intervals for marks distribution, classes 40–50 are typically split into:

Correct Answer Explanation

Class 40–50 is split into 40–45 and 45–50 (each with class interval of 5).

Unequal Class Interval Splits:

• 40–50 → 40–45 (freq: 9) and 45–50 (freq: 12)
• 50–60 → 50–55 (freq: 7) and 55–60 (freq: 16)
• 60–70 → 60–65 (freq: 10) and 65–70 (freq: 9)
• Other classes (0–10, 10–20, 20–30, 30–40, 70–80, 80–90, 90–100) retain class interval of 10.

Why:

To make class marks more representative of the concentrated data in those classes.