1. In this exercise, we examine the effect of the value of the estimated standard deviation...

1. In this exercise, we examine the effect of the value of the estimated standard deviation on determining the sample size needed.
Find the sample size needed to give, with 90% confidence, a margin of error within ±4, if the estimated standard deviation is σ˜=60. If the estimated standard deviation is σ˜=20. If the estimated standard deviation is σ˜=10.

σ˜=60 :	n=?
σ˜=20 :	n= ?
σ˜=10 :	n=?

2. In this exercise, we examine the effect of the confidence level on determining the sample size needed.
Find the sample size needed to give a margin of error within ±2 with 99% confidence. With 95% confidence. With 90% confidence. Assume that we use σ˜=30 as our estimate of the standard deviation in each case.

99% :	n= ?
95% :	n= ?
90% :	n= ?

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Expert Solution

orchestra answered 1 year ago

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