A population of n = 15 scores has a mean of μ = 8. One score in the population is changed from x = 20 to x = 5. What is the value for the new population mean

Mean = Sigma (summation) of x : n

(Making Sigma x The subject of the formula)

Summation of x = Mean * n

= 8 * 15

The summation of all the scores = 120

The change of x is 20-5 = 15

New summation = 120 - 15 = 105

Using formula:

105 : 15 = 7

ų = 7