[計量] OG綠本PS 70
題目
If a certain sample of a data has a mean of 20.0
and a standard deviation of 3.0, which of the following
values is more than 2.5 standard deviation from the mean?
(A) 12.0
(B) 13.5
(C) 17.0
(D) 23.5
(E) 26.5
看了他後面的詳解解釋是
The value must be more than 2.5 standard deviation
above the mean or below the mean.
2.5*3=7.5
20-7.5=12.5
20+7.5=27.5
The only value outside the range of 12.5 to 27.5 is 12.0
so the answer is A
看了詳解後還是無法理解他題目的要問的東西,
煩請高手板友們解惑(解釋題目要問的東西最後一句~"~)
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