CA Foundation · Quantitative Aptitude · Statistical Description of Data
The mean of a sample of 8 measurements is 24. If one measurement is removed, the mean of the remaining 7 measurements becomes 22. What was the value of the removed measurement?
The removed measurement was 38. Since the sum of 8 measurements at mean 24 is 192, and the sum of remaining 7 measurements at mean 22 is 154, the difference is 192 − 154 = 38.
- A18
- B32
- C40
- D38Correct
Explanation
Sum of 8 measurements = 8 × 24 = 192. Sum of 7 measurements = 7 × 22 = 154. Removed value = 192 − 154 = 38. The key concept is that the sum can be recovered from the mean and the count, and the difference in sums equals the removed value. Option 32 is a distractor from calculating 8 × 24 − 7 × 22 incorrectly.
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