Question

The mean of eight numbers is 27 .if one more no.is included then the mean is 26.find the included number

Answer 1

Answer:

The new number is 18.

Step-by-step explanation:

The mean of a set of data is computed using the formula: $\bar x=\frac{1}{n}\sum x_{i}$

The mean of 8 observations is 27.

Then the sum of 8 observations is:

$\bar x=\frac{1}{n}\sum x_{i}\\27=\frac{1}{8}\sum x_{i}\\\sum x_{i}=216$

The sum of eight observations is 216.

A new observation is added to this set.

The new mean of 9 observations is 26.

Compute the value of the new observation as follows:

$26=\frac{1}{9}[\sum x_{i}+x_{n}]\\234=[216+x_{n}]\\x_{n}=234-216\\=18$

Thus, the new number is 18.