SOLUTION: When σ = 10, what sample size is needed to specify a 95% confidence interval of ±3 units for the mean?

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Question 927156: When σ = 10, what sample size is needed to specify a
95% confidence interval of ±3 units for the mean?
Found 2 solutions by ewatrrr, stanbon:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
ME = 1.96 σ /sqrt(n)
n = (1.96 σ /ME)^2
n = (1.96 (10) /3)^2 = 42.684
sample size +highlight_green%2843%29 is needed

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
When σ = 10, what sample size is needed to specify a
95% confidence interval of ±3 units for the mean?
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n = [z*s/E]^2
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n = [1.96*10/3]^2 = 7 when rounded up.
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Cheers,
Stan H.