A sample of n = 8 scores has a mean of M = 10.After one score is removed from the sample,the mean for the remaining score is found to be M = 11.What was the score that was removed?
A)X = 3
B)X = 7
C)X = 8
D)Cannot be determined from the information provided

Question

Quizplus · Accepted Answer

Let the sum of the initial eight scores be S. Then, we have:

M = S/8 = 10

After one score is removed, let the remaining sum be R, and let the score that was removed be X. Then we have:

M = R/7 = 11

Using these two equations, we can solve for both S and X:

S = 8M = 80
R = 7M = 77

X = S - R = 3

Therefore, the score that was removed is X = 3.

A Sample of N = 8 Scores Has a Mean