在准备ＧＭＡＴ考试,看到这题目,根本没看懂题目的意思,请高手帮忙看下:
A researcher computed the mean,the median,and the standard deviation for aset of performance scores. If 5 were to be added to each score,which of these three statistics would change?
a. the mean only
b . the median only
c.the standard deviation only
d.the mean and the median
e. the mean and the standard deviation