Researchers studied the effect of road-junction design on travel efficiency. They created two four-way inter- sections (i.e., a crossroads). One intersection was a typical four-way stop: cars had to stop and wait for the way to be clear before they could drive through the intersection. The other intersection used a roundabout: cars only had to stop if another car was already in the roundabout. They timed how long it took for cars to pass though the intersection in moderately heavy traffic conditions. A sample of 8 cars were monitored at the four-way-stop intersection. Here are their times (in seconds): 9, 13, 14, 14, 15, 11, 11, 14. A sample of 9 cars were monitored at the roundabout intersection. Here are their times (in seconds): 10, 3, 12, 15, 9, 15, 9, 9, 8. Calculate the mean time (and standard deviation) taken by the cars in each intersection and analyze the data to determine if the means are significantly different. Calculate the effect size, Cohen's d. Report your findings as a sentence or two that could be in the Results section of an APA-style research article.