A sample of n 7 scores has a mean of M 5 After one new sco

A sample of n = 7 scores has a mean of M = 5. After one new score is added to the sample, the new mean is found to be M = 6. What is the value of the new score? Give you answer as a whole number (that is, give a number like 1, 2, 3... no decimal or fractional part).

(Hint: Compare the values for X before and after the score was added.)

Solution

As

Sum(x) = n*mean

Then

Old Sum(x) = 7*5 = 35

But

New Sum(x) = 8*6 = 48

Hence, the last number is

Last number = 48 - 35 = 13 [ANSWER]