the life expectancy of a particular brand of hair dryer is normally distributed with a mean of four years and a standard deviation of eight months. this Equates to (60-48)/8 = 1.5 and .9332 then1- .9332=.0668
The company has a three year warranty period on its hair dryers. what percentage of its hair dryers will be in operating condition after the warranty period? (36-48)/8 = - 1.5 and .0068 then1- ..0068=.9332
what is the minimum and the maximum life expectancy of the 90% of the hair dryers? on this problem I am lost.