lsat做了一半了,怎么PP3的数学都看不懂了呢?郁闷啊郁闷......

阿狼

这个是PP3的原题.

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?

答案是10.5
我想问的是带问号的问题到底是什么意思啊?

lisaislisa

13.5-2*1.5=10.5
for the rational of this kind of Pro , pls consult to statistics
but these are no more than some basic points

^^