Exercise 2.144 on page 102 describes a study conducted by engineers in Dresden, Germany looking at ways to improve traffic flow by enabling traffic lights to communicate with each other in real time. They simulated buses moving along a street and recorded the delay time (in seconds) for both the current fixed timed system and a flexible interacting system of lights. They repeated the simulation in each case for a total of 24 situations. The data in TrafficFlow show the total delay time (in minutes) for both the Timed and the Flexible simulations for each run, as well as a column showing the Difference in the time for each pair, with Difference = Timed − Flexible in each case. Use statistical software to find a 95% confidence interval for the mean difference in delay time between the two systems and to conduct a hypothesis test to see if there is a difference in delay times between the two systems. Interpret the confidence interval and include all details of the test. Which method has the least average delay time for traffic?

Exercise 2.144

Have you ever driven along a street where it seems that every traffic light is red when you get there? Some engineers in Dresden, Germany, are looking at ways to improve traffic flow by enabling traffic lights to communicate information about traffic flow with nearby traffic lights. The data in TrafficFlow show results of one experiment that simulated buses moving along a street and recorded the delay time (in seconds) for both a fixed time and a flexible system of lights. The simulation was repeated under both conditions for a total of 24 trials.