Answer:
C. The mean increases by 0.75.
Explanation:
The mean of a data set is given by the sum of all its values, divided by the number of values.
Data set {10, 2, 8, 9, 5, 2, 6}
7 values
Sum: 10 + 2 + 8 + 9 + 5 + 2 + 6 = 42
Mean: 42/7 = 6
Adding number 12 to the data set
Now we have 8 values
The sum is 42 + 12 = 54
The mean is 54/8 = 6.75
This means that the mean increases by 0.75.