Question

According to one study, the amount of time a customer spends shopping in a grocery store is normally distributed with a mean of 45 minutes and a standard deviation of 12 minutes. Let X be the number of minutes that a customer spends shopping in a grocery store on one visit. Calculate the probability that a customer spends at least 50 minutes shopping.

Answer 1

Solution :

Given that ,

mean = = 45

standard deviation = = 12

P(x 50) = 1 - P(x   50)

= 1 - P((x - ) / (50 - 45) / 12)

= 1 -  P(z 0.4167)  

= 1 - 0.6616   

= 0.3384

P(x 50) = 0.3384

Probability = 0.3384