MS 150 Statistics Quiz 08 Fall 2004 9.1 • Name: _______________

A sample size n of 22 male students in MS 150 had their body fat measured. The sample mean body fat x is 18.85 with a sample standard deviation sx of 8.63. Construct a 99% confidence interval for a population mean male body fat.

1. The confidence interval for the population mean male body fat µ is:
   
   P( _________ ≤ µ ≤ _________ ) = 0.99
2. _______ Could the population mean male body fat be above 20%, the lower limit for being overfat, at a 99% confidence level?

Statistic or Parameter	Symbol	Equations	Excel
Confidence interval statistics
Find z from the area under the normal curve to the left of z	z		=NORMSINV(area to the left of z)
Calculate an x value from z, sx, n and a point estimate of µ			=z*sx/SQRT(n)+µ