推 sleepsoy:謝謝!!!! 01/10 12:50
※ 引述《sleepsoy (洪小義)》之銘言：
: Suppose that the scores of an exam with fifty thousand attendants have normal
: distribution with the variance of 16, and 15.87% of the attendants have scores
: less than 68 points. With the information of the Q-function below, you may use
: interpolation to obtain the estimated value when necessary.
: a.
: What is the mean value of scores in this exam?
: 想請問板上的高手
: mean的值要怎麼求...
: 謝謝QQ
the score r.v. X~N(M,16)
P(X<68)=0.1587 =>P(Z<(68-M)/4)=0.1587
where (68-M)/4=-1 =>M=72 #
應該用不到C.L.T @@
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