Suppose the wait through immigration at JFK Airport in New York is thought to be bell-shaped and symmetrical with a mean of 22 minutes. It is known that 68 percent of travelers will spend between 16 and 28 minutes waiting to pass through immigration. The standard deviation for the wait time through immigration is
A)8 minutes.
B)9 minutes.
C)10 minutes.
D)6 minutes.

Question

Quizplus · Accepted Answer

The standard deviation can be determined from the given information that 68% of travelers wait between 16 and 28 minutes, which corresponds to the mean (22 minutes) plus and minus one standard deviation in a normal distribution. The difference between the mean and either the upper or lower bound of this range (22 - 16 = 6 or 28 - 22 = 6) is the standard deviation, which is 6 minutes.

Suppose the Wait Through Immigration at JFK Airport in New