Asked by deborah
A manufacturer knows that their items have a normally distributed lifespan, with a mean of 7.5 years, and standard deviation of 1.7 years.
If you randomly purchase one item, what is the probability it will last longer than 9 years? (Give answer to 4 decimal places.)
Incorrect
If you randomly purchase one item, what is the probability it will last longer than 9 years? (Give answer to 4 decimal places.)
Incorrect
Answers
Answered by
oobleck
9 years is (9-7.5)/1.7 = 0.833σ above the mean.
Now consult your Z table.
Now consult your Z table.