Assume that police estimate that 30% of drivers do not wear their seatbelts. They set up a safety roadblock, stopping cars to check for seatbelt use. They stop 40 cars during the first hour.
a. Find the mean, variance, and standard deviation of the number of drivers expected not to be wearing seatbelts. Use the
fact that the mean of a geometric distribution is j = and the variance is 02 - 9
1
р
2
b. How many cars do they expect to stop before finding a driver whose seatbelt is not buckled?
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물
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The mean is
(Round to the nearest tenth as needed.)
The variance is
(Round to the nearest tenth as needed.)
The standard deviation is
(Do not round until the final answer. Then round to the nearest tenth as needed.)
They expect to stop cars before finding a driver whose seatbelt is not buckled.
(Round to the nearest tenth as needed.)