SOLUTION: A recent survey revealed that an American's Christmas spending averaged $830. Use this as the population mean American's Christmas spending. Suppose Americans' Christmas spending i

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Question 1187723: A recent survey revealed that an American's Christmas spending averaged $830. Use this as the population mean American's Christmas spending. Suppose Americans' Christmas spending is normally distributed with a standard deviation of $220. A random sample of size 100 is selected from the population of American consumers. The middle 90% of the sample mean spending will be bounded by what two values?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
This is a 90% confidence interval.
the half-interval is z(0.95)*sigma/sqrt(n)
=1.645*220/sqrt(100)
=36.19
The mean of this sampling distribution Is 830, same as population mean
the interval is ($793.81, $866.19)