Question 1192927
a. z=(x-mean)/sd so z< (40-85)/25=-45/25 or -1.8
That probability is 0.0359
b. for two tests the expectation of the mean is still 85 mg%
The SE is the sd/sqrt(n) or 25/sqrt(2)=17.68
now z would b <-40/17.68=-2.26
That probability is 0.0119