A manufacturer claims that the mean
lifetime of its drill is 1000 hours. A
homeowner selects 25 drills and finds
the mean lifetime to be 980 hours with a
sample standard deviation of 80 hours.
If = 0.05, test the manufacturer's claim.
A manufacturer claims that the mean
lifetime of its drill is 1000 hours. A
homeowner selects 25 drills and finds
the mean lifetime to be 980 hours with a
sample standard deviation of 80 hours.
If = 0.05, test the manufacturer's claim.