To cross the bay bridge in san francisco, the magic number of riders in a vehicle is three. this allows the car to utilize the carpool lane, thus avoiding clogged freeways and backup at the bridge's tollbooths.
casual carpool, a decades-old hitchhiking system, is outdoing uber, lyft, and waze.
according to a transit study concerning people that use casual carpool, more than 6,000 people use the system per day.
the median wait time for riders at a casual carpool stop is 2 1 2 minutes.

describe the population and sample for this study scenario.