Why Unequal Intervals Give Better Class Marks
Which of the following best describes why class marks are more representative in unequal class intervals?
- Unequal intervals eliminate all loss of information
- Observations in split classes deviate less from their new class marks than from the old class marks — Correct Answer
- Unequal intervals always produce more classes
- Unequal intervals are mandatory for continuous variables
Explanation:
Correct Answer Explanation
In unequal class intervals, observations deviate less from their new class marks than from the old class marks — making new class marks more representative.
Example:
- Old class 40–50 (class mark 45): observations like 47, 49, 48 deviate significantly from 45.
- New class 45–50 (class mark 47.5): same observations deviate much less from 47.5.
Key Principle:
Classes should be formed so that class marks coincide as closely as possible to values around which observations concentrate — this minimises the error from substituting class mark for actual values.
📚 About this Topic — CH-3: Organisation of Data
This multiple choice question is from CH-3: Organisation of Data, NCERT Books, Statistics for Economics. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from CH-3: Organisation of Data to strengthen your preparation.
