A Palo Alto resident believed cars were still speeding on his street after the implementation of the traffic-calming measures. He took several different random samples of cars and, using a radar gun, recorded the speed of each car as it passed his house. Each of his random samples was of a different sample size, but surprisingly, all of his random samples had the same mean speed ( x = 25.5 MPH) and the same standard deviation (s = 3.618). (Of course, this is not really what happened. This example is for illustrative purposes to examine the idea of statistical significance versus practical significance.)