The mean of 20 observations is 22.5. One observation was wrongly noted as -25 instead of 25. The correct mean is:

Correct option is B

Given:

The mean of 20 observations = 22.5

One observation was wrongly noted as -25 instead of 25

Formula used:

Mean = sum of observations/Number of observations

Solution:

The mean of 20 observations = (20 × 22.5)

=> 450

Now,

The correct sum = 450 - (-25) + 25

=> (475 + 25) = 500

The correct mean = $$\frac{500}{20}$$​​

=> 25

∴ The correct mean is 25.