Question

The mean of 20 observations was 50. Later it was found that an observation 42 was wrongly taken as 24. The corrected new mean is
1. 49.1
2. 50.9
3. 51.9
4. 60

Answer 1

Correct Answer - Option 2 : 50.9

GIVEN:

The mean of 20 observations = 50 and 42 was wrongly taken as 24

CALCULATION:

The mean of 20 observations = 50 

⇒ Correct sum = (20 × 50 + 42 - 24) 

⇒ 1000 + 18 

⇒ 1018

⇒ Correct mean = 1018/20

⇒ 50.9

∴ Correct mean = 50.9