Preston, an official for a state’s department of safety, wants to show that the population mean speed of passenger

vehicles traveling on a certain expressway is greater than the posted speed limit of 65mph. Preston collects a random sample of 59 passenger vehicles traveling on the expressway and finds that the sample mean speed is 67.1mph

 with a sample standard deviation of 7.5mph. The test statistic t for a hypothesis test of H0:μ=65 versus Ha:μ>65 is t≈2.15

 with 58 degrees of freedom. If 0.01

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