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Homework 5: Question 2
The 92 million Americans of age 50 and over control 50%  of discretionary income.  AARP estimates
that the average annual expenditue on  restaurants and carryout food was $1,873 for individuals in
this age group.  Suppose this estimate is based on a sample of 80 persons and that the sample standard
deviation is $550.
a) At a 95% confidence, what is the margin of error?
b) What is the 95% confidence interval for the population mean amount spent on restaurants and carryout food?