OG Diagnostic Quatitative 讨论

No. 9 of Quantitative section.

A researcher computed the mean, the median, and the standard deviation for a set of performance scores. If 5 were to 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

Which one do you think is the right answer? Why?

Thanks!

应该选d吧

若每个数都加5，则平均数在原来的基础上加5，中数也加5，标准方差不变（根据标准方差的公式可以得出）。