SOLUTION: A manufacturer knows that their items have a normally distributed lifespan, with a mean of 9.9 years, and standard deviation of 3.1 years. The 4% of items with the shortest life

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Question 1145360: A manufacturer knows that their items have a normally distributed lifespan, with a mean of 9.9 years, and standard deviation of 3.1 years.
The 4% of items with the shortest lifespan will last less than how many years?

Answer by VFBundy(438)   (Show Source): You can put this solution on YOUR website!
Go to a z-table and find the value that corresponds with a score of 0.04. The closest z-score is -1.75.



Cross-multiply:

x - 9.9 = -5.425

x = 4.475

The 4% with the lowest lifespan will last less than 4.475 years.

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