Chaoyun L. answered • 11/06/15

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Master of Math with concentration in Statistics

A. z= (x-µ)/σ = (170-150)/20 =1

From the z-table, we can get the upper tail p vaule = 0.1587

so 15.87% will exceed.

B. Z upper tail p value <0.1 has Zscore 1.28

So 1.28 = (x-150)/20

x=175.6