A sample of n = 5 scores has a mean of M = 12.One new score is added to the sample,and the new mean is calculated to be M = 11.What is the value of new score?
A)X = 5
B)X = 6
C)X = 12
D)X = 60

Question

Quizplus · Accepted Answer

Let the sum of the initial five scores be S1. Then, we have:
S1/5 = 12, which gives S1 = 60.
After the new score is added, the sum becomes S1 + X, and the number of scores becomes n + 1 = 6.
Thus, the new mean is (S1 + X)/6 = 11.
Solving for X, we get X = 6.

A Sample of N = 5 Scores Has a Mean