Moderate# Flight Delays

APSTAT-EPJYYG

Air travel can be very frustrating when flights don't leave on time! Over the last 5 months, 15% of Be Free Airline flights were delayed. For the same time period, 20% of Fly Me Away Airline flights were delayed.

In the process of investigating the difference between the two airlines, a consumer's group randomly selects 80 flights from each company during this time period and finds the proportion of flights that were delayed for each. They calculate the standard deviation of the sampling distribution of the difference between these two proportions. Their calculations are shown below:

${ \sigma }_{ { p }_{ B }-{ p }_{ F } }=\sqrt { \frac { (0.15)(0.85) }{ 80 } } +\sqrt { \frac { (0.20)(0.80) }{ 80 } } =0.085$

Which of the following statements is **true**?