Question

Mean of 9number is 14 one number 12 was excluded.find the new mean

Answer 1

New mean = 14.25

Step-by-step explanation:

We are given that the Mean of 9 numbers is 14 and one number 12 was excluded.

We have to find the new mean.

As we know that Mean formula, $\bar X = \frac{\sum X}{n}$

where,  = Total Sum of n observation

                  n = Number of observation

So, Total Sum of n observation ($\sum X$) =  

                          $\text{Mean} (\bar X) \times \text{Number of observation} (n)$  

Total sum of all 9 numbers, $\sum X$  = $14 \times 9$ = 126

Now, we are given that 12 is excluded from the data;

So, New  $\sum X$ = 126 - 12 = 114

Also, new n = 9 - 1 = 8

Therefore,  New Mean =  $\frac{\text{New} \sum X}{\text{New n}}$

                                      =  $\frac{114}{8}$

                                      =  14.25

Hence, the new mean is 14.25.