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# Confidence Intervals and Population Means

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Construct a 95% confidence interval to estimate the population mean with a sample mean = 110 and ? = 30 for the following sample sizes:

a) n = 30
b) n = 45

Please write confidence interval in parentheses with the lower confidence limit first, followed by the upper limit, separated by a comma.

https://brainmass.com/statistics/confidence-interval/confidence-intervals-population-means-522740

#### Solution Preview

a) n = 30
The confidence interval is given by , where = 110, Ïƒ = 30, n = 30, = 1.959963985
That is,
= (99.26, 120.74)
Thus with 95% confidence we can claim that population mean is within (99.26, 120.74).
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Confidence Interval Estimate for the Mean

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#### Solution Summary

The expert examines confidence intervals and population means.

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