What happens to the mean of the data set {2, 4, 5, 6, 8, 2, 5, 6} if the number 7 is added to the data set?

A. The mean decreases by 1.
B. The mean increases by 2.
C. The mean increases by 0.25.
D. The mean increases by 0.75

2+4+5+6+8+2+5+6= 38/8 = 4.75

2+4+5+6+8+2+5+6+7 = 45/9 = 5

5 - 4.75= 0.25

C. The mean increased by 0.25

C) the mean increases by 0.25

Step-by-step explanation:

First you cauculate the mean of the data set already in the parentheses by adding all of the numbers together and dividing it by the total amount of numbers in the set. Then you do the same thing but add the 7 in.