Question

the mean of 10 observations is 65. by an error, one observation is registered as 15 instead of - 15.find the correct mean​

Answer 1

Answer:

Correct Mean = 62 .

Step-by-step explanation:

We are given that the mean of 10 observations is 65.

Also, by an error one observation is registered as 15 instead of - 15.

The Mean formula is given by = Sum of all values ÷ Number of observations

So, Original Mean = $\frac{\sum X}{n}$

           65   =   $\frac{\sum X}{10}$

So, incorrect ∑X = 65 * 10 = 650.

Correct ∑X = 650 - 15 + (-15) = 650 - 30 = 620.

Therefore, Correct Mean =  $\frac{Correct \sum X}{10}$

                                          =  $\frac{620}{10}$ = 62 .