Question

Parking concerns ~ Over the years, parking has become an issue during spring at MSU as more people bring cars to campus. The waiting time to find a parking spot at Wells Hall parking lot is normally distributed with an average of 10 minutes and a standard deviation of 3.6 minutes during peak hours (10 am – 5 pm).

What is the waiting time for the 20th percentile? Enter your answer to 4 decimal places.

Your Answer:

Answer 1

Given that,

mean =  = 10

standard deviation =  = 3.6

Using standard normal table,

P(Z < z) = 20%

=(Z < z) = 0.20

= P(Z < z ) = 0.20  

z = -0.84

Using z-score formula  

x = z +

x = -0.84*3.6+10

x = 6.9760