Question

The wait times in line at a grocery store are roughly distributed normally with an average wait time of 7.6 minutes and a standard deviation of 30 seconds. What is the probability that the wait time is between 6 and 7.3 minutes

Answer 1

Answer:

the probability that the wait time is between 6 and 7.3 minutes = 0.725

Step-by-step explanation:

Given -

Average wait time  $(\nu)$  =  7.6 minutes

Standard deviation $(\sigma)$ = 30 second = .5 minute

Let X be the wait times in line at a grocery store

the probability that the wait time is between 6 and 7.3 minutes

[ Put z = $\frac{X - \nu }{\sigma}$ ]

$P (7.3> X>6 )$ = $P (\frac{7.3 - 7.6}{.5}> Z>\frac{6 - 7.6 }{.5} )$

                         = $(.6> Z> -3.2 )$

[Using z table]

                         = Area to the left of z = .6 - area to the left of z = -.32

                         = .7257 - .0007 = 0.725