SOLUTION: A researcher wishes to estimate the mean amount of money spent per month on food by households in a certain neighborhood. She desires a margin of error of $30. Past studies suggest
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Question 1036564: A researcher wishes to estimate the mean amount of money spent per month on food by households in a certain neighborhood. She desires a margin of error of $30. Past studies suggest that a population standard deviation of $248 is reasonable. Estimate the minimum sample size needed to estimate the population mean with the stated accuracy.
A. 274
B. 284
C. 264
D. 272 Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! the standard error is sigma/square root (n). That is multiplied by the z value for a presumed 95% CI (1.96)
30=1.96*248/sqrt(n), if we use a 95% CI.
square both sides
900=3.84*61504/n
n=61504/900
=262.52
round up to 263. Best choice is 264.
