Confidence interval helps
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# Confidence interval helps

[From: ] [author: ] [Date: 11-10-07] [Hit: ]
09).(a) Without doing any computation, would the 95% confidence interval be wider, narrower, or about the same if we increase the sample size of the population? Let say the sample size increase from 86 to 500.......
A zoologist measured tail length in 86 individuals, all in the one-year age group, of the deermouse Peromyscus. The mean length was 60.43 mm and the standard deviation was 3.06 mm. A 95% confidence interval for the mean is (59.77, 61.09).

(a) Without doing any computation, would the 95% confidence interval be wider, narrower, or about the same if we increase the sample size of the population? Let say the sample size increase from 86 to 500. Explain?
(b) Without doing any computation,would the 80% confidence interval comparing with 95% interval be wider, narrower, or about the same, and why?

Thanks for help

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a) When the sample size is increased, the margin of error becomes smaller.
As such the confidence interval will be NARROWER.

b) When the confidence interval is reduced, the margin of error becomes smaller.
As such the 80% confidence interval will be NARROWER.
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