SOLUTION: An inspector wants to estimate the weight of detergent in packets filled, by an automatic filling machine. She wants to be 95% confident that her estimate is not away from the true

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Question 1011878: An inspector wants to estimate the weight of detergent in packets filled, by an automatic filling machine. She wants to be 95% confident that her estimate is not away from the true mean weight of detergent by more than 10 gms. What should the minimum sample size be if it is known that the standard deviation of the weight of detergent filled by that machine is 100 gms?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
An inspector wants to estimate the weight of detergent in packets filled, by an automatic filling machine. She wants to be 95% confident that her estimate is not away from the true mean weight of detergent by more than 10 gms. What should the minimum sample size be if it is known that the standard deviation of the weight of detergent filled by that machine is 100 gms?
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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*100/10]^2
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n = [1.96*10]^2
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n = 19.6^2 = 385 when rounded up
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Cheers,
Stan H.
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