SOLUTION: How large should the size of a random sample be so that we can be 90% certain that the sample mean X will not deviate from the true mean by more than σ/2?
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-> SOLUTION: How large should the size of a random sample be so that we can be 90% certain that the sample mean X will not deviate from the true mean by more than σ/2?
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Question 1178274: How large should the size of a random sample be so that we can be 90% certain that the sample mean X will not deviate from the true mean by more than σ/2?
thank you Found 2 solutions by Boreal, ewatrrr:Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! the error, e,=sigma/sqrt(n)*z(0.95)
e^2=2.706*sigma^2/n, squaring everything including z=1.645
e=sigma/2 so e^2=sigma^/4
so sigma^2/4=2.706 sigma^2/n
n=10.0824 or 11.
