Question

An automatic tire inflator pump is designed so that it pumps an average of 3.2 psi air into empty tires in a car manufacturing factory. Tires for that specific model of car are considered over-inflated if their pressure is above 3.6 psi. Also, the tires are dangerously under-inflated if the pressure is below 2.9 psi. It is known that the amount of pumped air is normally distributed and the standard deviation is 0.484 psi.

a) How many tires will probably be over inflated during pumping the next 1000 tires?

b) below what value (of air pressure) do we get the 8% of the inflated tires with lowest pressures?

c) What does the conclusion of part b reveal? Is it concerning?

Answer 1