Question 1
A sample of 225 elements from a population with a standard deviation of 75 is selected. The sample mean is 180. The 95% confidence interval for μ is
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105.0 to 225.0
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175.0 to 185.0
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100.0 to 200.0
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170.2 to 189.8
Question 2
After computing a confidence interval, the user believes the results are meaningless because the width of the interval is too large. Which one of the following is the best recommendation?
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Increase the level of confidence for the interval.
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Decrease the sample size.
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Increase the sample size.
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Reduce the population variance.