A manufacturer knows that their items have a normally distributed lifespan, with a mean of 11.6 years, and standard deviation of 2.9 years. If you randomly purchase 16 items, what is the probability...

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 11.6 years, and standard deviation of 2.9 years.


If you randomly purchase 16 items, what is the probability that their mean life will be longer than 13 years?