Central Tendency & DispersionMTP Nov 19Question 2884 of 473
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The mean of four observations is 10 and when a constant a is added to each observation, the mean becomes 13. The value of a is

Options

A2
B-3
C3
DNone of these
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Correct Answer

✅ Option c — 3

All Options:

  • A2
  • B-3
  • C3
  • DNone of these

Detailed Solution & Explanation

**Step 1: Apply the property of arithmetic mean.** When a constant a\displaystyle a is added to each observation, the new mean =\displaystyle = old mean +a\displaystyle + a. New mean=10+a=13\text{New mean} = 10 + a = 13 a=13−10=3a = 13 - 10 = 3 **Note:** The computed answer is a=3\displaystyle a = 3 (Option C), not 2 (Option A). The correct computation gives a=3\displaystyle a = 3. Hence, **Option C** is the correct answer.

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