The average numbers of days it took Chicago€™s Department of Streets & Sanitation to respond to requests to fix potholes are described by the density histogram in Fig. 96 for each of the weeks in 2012 and 2013.

a. Identify the class that contains the 50th percentile, which is a measure of the center. Are the observations in the class typical values? Explain.
b. For what proportion of the weeks was the average response time at least 42 days? Some of the bars in the density histogram were left blank on purpose.
c. From inspecting the histogram, a student concludes that in 2015, the average response time will be less than 21 days for 79% of the weeks. What would you tell the student?
d. The department has a target that the average time to respond to pothole requests made in a given week be less than 7 days. Find the proportion of observations that are less than 7 days.
e. Suppose the department decides to change the target to be less than 14 days. Find the proportion of observations that are less than 14 days.

Transcribed Image Text:

Average Response Time to Fix Potholes 0.05 0.04 2 0.03 0.02 0.01 2 0.340.33 0.12 0.081 0.07 7 14 21 28 35 42 49 56 63 70 77 Days