中等MATH-STAT-003
If every score in a data set is increased by 5, what happens?
A. The mean increases by 5 and the standard deviation increases by 5
B. The mean increases by 5 and the standard deviation is unchanged✓ 答案
C. Both the mean and the standard deviation stay the same
D. The mean is unchanged and the standard deviation increases by 5
解說
Adding 5 shifts every point, so the mean rises by 5. The gaps between points are unchanged, so the standard deviation stays the same.