Question

A random sample of 80 tires showed that the mean mileage per tire was 41,400mi, with a standard deviation of 4700mi

Answer 1

Question 14

Part (a)

`(46800-41400)/(4700) \approx \boxed{1.15}`

Part (b)

`-2.57=(x-41400)/(4700) \\ \\ -2.57(4700)=x-41400 \\ \\ x=41400-2.57(4700) \\ \\ x \approx \boxed{29300}`