Question

the mean of 15 observation is 20 if 8 is added to each observation, find the new mean

Answer 1

since the mean of the observation is 20 and 8 is added to each number
therefore new mean =20+8=28

Answer 2

Given that the mean of 15 observations = 20.

Therefore the sum of observations = 15 * 20

                                                           = 300.

Given that if 8 is added = 300 + (15 * 8)

                                        = 300 + 120

                                        = 420.


The new mean = Sum of observations/Number of observations

                          = 420/15

                          = 28.


Hope this helps!