SOLUTION: 8.1 #5 A simple random sample of size n=12 is obtained from a population with μ=69 and σ=16. = (a) What must be true regarding the distribution of the population in

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Question 1077769: 8.1 #5
A simple random sample of size n=12 is obtained from a population with
μ=69 and σ=16.
=
(a) What must be true regarding the distribution of the population in order to use the normal model to compute probabilities involving the sample​ mean? Assuming that this condition is​ true, describe the sampling distribution of
x ( with overbar on top of x).
​(b) Assuming the normal model can be​ used, determine ​P(x<72.2​).
​(c) Assuming the normal model can be​ used, determine ​P(x≥70.7​).



I know what A is, μx=69 and σ=16/the square root of 16
I just don't know what b or c are. thank you!



Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
z=(72.2-69)/(16/sqrt(12))--not sqrt (16)
=0.6928
probability < 0.6928 is 0.7558.
probability x > 70.7 is z > (1.7)/16/sqrt(12)=0.3680
That probability is 0.3564

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