Question

Demand per hour for gasoline at a local station is normally distributed with a mean of 875 gallons and std deviation of 55 gallons. What is the probability that demand for a particular hour is between 800 and 900 gallons? Enter your answer as a decimal, rounded to 4 decimal places.

Answer 1

Let X be the random variable which represents the demand for gasoline per hour at local station.

Then X ~ N(875 , 55^2)

So for finding P(800 < X < 900) we have:

Where Z follows standard normal distribution and is the cdf of standard normal distribution whose value can be found from the Z-tables or the standard normal cdf tables. So substituting the value from the tables we get:

Thank you! Please rate positively if satisfied!