Question 759866
a.
A random sample of 25 was drawn from a normal distribution with a standard deviation of 5. The sample mean is 80. Determine the 95% confidence interval estimate of the population mean.
ME = 1.96*[5/sqrt(25)] = 1.96
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95% CI: 80-1.96 < u < 80+1.96
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b.
Repeat part (a) with a sample size of 100.
ME = 1.96*[5/sqrt(100)] = 1.96*1/2 = 0.98
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95% CI: 80-0.98 < u < 80+0.98
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c.
Repeat part (a) with a sample size of 400.
I'll leave that to you.
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d.
Describe what happens to the confidence interval estimate when the sample size increases.
The interval gets smaller.
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Cheers,
Stan H.
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