SOLUTION: The mean life of an appliance manufactured by your company is 10 years with a standard deviation of 3.5 years. What is the Z value to find the area for a machine that lasted 13

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Question 1087807: The mean life of an appliance manufactured by your company is 10 years with a standard deviation of 3.5 years.
What is the Z value to find the area for a machine that lasted 13 years?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
z+=+%28x+-+mu%29%2F%28sigma%29 Start with the z-score formula.

z+=+%28x+-+10%29%2F%28sigma%29 Plug in the mean mu+=+10 (mu is the greek letter mu)

z+=+%28x+-+10%29%2F%283.5%29 Plug in the standard deviation sigma+=+3.5 (sigma is the greek letter sigma)

z+=+%2813+-+10%29%2F%283.5%29 Plug in the raw score x+=+13

z+=+3%2F3.5 Subtract in the numerator

z+=+0.85714285714286 Divide

z+=+0.86 Round to the nearest hundredth (refine the accuracy however you need to)

The z value is roughly z+=+0.86