PP-T2-PS44

[Huang Hsin-Yi]

44. 5884-!-item-!-187;#058&004663
The arithmetic mean and standard deviation of a certain normal distribution are 13.5 and 1.5, respectively. What value is exactly 2 standard deviations less than the mean?

(A) 10.5
(B) 11.0
(C) 11.5
(D) 12.0
(E) 12.5

Ans:A

請問它問的標準差概念是什麼?

[gman]

What value is exactly 2 standard deviations less than the mean
意思就是 mean - 2(standard deviation) ==> 13.5-2*1.5 ==>A

[Huang Hsin-Yi]

謝謝,懂了