Question 286131: I sent the below question in last night. I know my Xbar is 20.4, my S is .5 and my CI is 95% I am trying to solve for n correct? The only equation my stats teacher taught us last week is t = xbar - mu over s/square root of n.....I can't find n without t so i don't know how to start this. I don't need you to solve it for me just point me in the direction of how to find either t or n and I can solve it. Thank you.
A processor of carrots cuts the green top off each carrot, washes the carrots,
and inserts six to a package. Twenty packages are inserted in a box for shipment. To test the weight of the boxes, a few were checked. The mean weight was 20.4 pounds, the standard deviation .5 pounds. How many boxes must the processor sample to be 95 percent confident that the sample mean does not differ from the population mean by more than .2 pound?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A processor of carrots cuts the green top off each carrot, washes the carrots,
and inserts six to a package. Twenty packages are inserted in a box for shipment. To test the weight of the boxes, a few were checked. The mean weight was 20.4 pounds, the standard deviation .5 pounds. How many boxes must the processor sample to be 95 percent confident that the sample mean does not differ from the population mean by more than .2 pound?
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The formula for sample sample size is derived from the
formula for standard error.
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Since E = z*s/sqrt(n)
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n = [z*s/E]^2
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Your Problem:
n = [1.96*0.5/0.2]^2 = 24.01
Rounding up, n = 25
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Cheers,
Stan H.
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