SOLUTION: A manufacture of TV tube has for many years used a process giving a tube mean life of 4700 hours and standard deviation of 1460 hours. A new process is tried to see if it will incr

Question 1199405: A manufacture of TV tube has for many years used a process giving a tube mean life of 4700 hours and standard deviation of 1460 hours. A new process is tried to see if it will increase the life significantly. A sample of 100 new tubes gave a mean life of 4700 hours. Is the new process better than the old at one percent level of significance?
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
i would guess that no improvement, since the mean life of the sample is the same as the mean life that is assumed for the population.
perhaps an error in the numbers you used?
z-score would be (4700 - 4700) / (1460 / sqrt(100)) = 0
area to the left or right of a z-score would be equal to .5.
that would be well above critical area of .01.

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