Question 1171705: Hinton Press hypothesizes that the average life of its largest web press is 14,500 hours. They know that the standard deviation of press life is 2,100 hours. From a sample of 25 presses, the company finds a sample mean of 13,000 hours. At a 0.01 significance level, should the company conclude that the average life of the presses is less than the hypothesized 14,500 hours?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Ho: life is >=14500
Ha: life is <14500
alpha=0.01 p{reject Ho|Ho true}
test is a z
critical value is z < 2.576
t=(13000-14500)/2100/sqrt(25)=-7500/2100=-3.57
reject Ho. The average life of the presses is < 14,500 hours
p=0.0002
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