Question

need help

The average price of a laptop is $982. Assume laptop prices are approximately normally distributed with a standard deviation of $100. The most expensive 15% of laptops cost less than what amount?

Answer 1

Solution :

Given that ,

mean = = 982

standard deviation = = 100

The z - distribution of the 15% is,

P( Z < z ) = 15 %

P( Z < z ) = 0.15

P( Z < -1.036 ) = 0.15

z = -1.036

Using z - score formula,

X = z * +

= -1.036 * 100 + 982

= 878.4