Question
Results from a survey of urban traffic are summarized in the table below showing the number of cars allocated to each of four categories of average speed. Average speed (mph) 20 30 40 50 Number of cars 86 123 168 56 In a subsequent survey the speeds of 24 independent cars were measured. Among those 24 cars: a) What is the expected number of cars that would be allocated to an average speed less than 30 mph? b) What is the probability that exactly 15 cars would be allocated to an average speed less than 30 mph? What is the probability that at least 7 cars would be allocated to an average speed less than 30 mph? c)
Explanation / Answer
Results from a survey of urban traffic are summarized in the table below showing the number of cars allocated to each of four categories of average speed. Average speed (mph) 20 30 40 50 Number of cars 86 123 168 56 In a subsequent survey the speeds of 24 independent cars were measured. Among those 24 cars: a) What is the expected number of cars that would be allocated to an average speed less than 30 mph? b) What is the probability that exactly 15 cars would be allocated to an average speed less than 30 mph? What is the probability that at least 7 cars would be allocated to an average speed less than 30 mph? c)