Suppose we wish to calculate a 90% confidence interval for the average amount spent on books...
Suppose we wish to calculate a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of $2. Assume that the amount spent on books by freshmen has a Normal distribution with a standard deviation of U = $30.How many observations are required to achieve this margin of error?
Homework Answers
sample size = ( Z * 
/ E )2
= ( 1.645 * 30 / 2 )2
= 608.86
Sample size = 609 (Rounded up to nearest integer)
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Suppose we wish to calculate a 90% confidence interval for the
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