In a study of the feasibility of a red light camera
In a study of the feasibility of a red-light camera program in the city of
Milwaukee, the data above summarize the projected number of crashes at 13 selected intersections over a 5-year period.
(a) Identify the variables presented in the table.
(b) State whether each variable is qualitative or quantitative. If quantitative, state whether it is discrete or continuous.
(c) Construct a relative frequency distribution for each system.
(d) Construct a side-by-side relative frequency bar graph for the data.
(e) Determine the mean number of crashes per intersection in the study, if possible. If not possible, explain why.
(f) Determine the standard deviation number of crashes, if possible. If not possible, explain why.
(g) Based on the data shown, does it appear that the red-light camera program will be beneﬁcial in reducing crashes at the intersections? Explain.
(h) For the current system, what is the probability that a crash selected at random will have reported injuries?
(i) For the camera system, what is the probability that a crash selected at random will have only property damage?
The study classiﬁed crashes further by indicating whether they were red-light running crashes or rear-end crashes. The results are as follows: