A Company Makes a Device That Can Be Fitted to Automobile

Essay

A company makes a device that can be fitted to automobile engines to improve the mileage.The company claims that if the device is installed,owners will observe a mean increase of more than 3.0 mpg.Assuming that the population standard deviation of increase is known to be 0.75 mpg,and a sample of size 64 cars is selected with an = 3.25 mpg,use the p-value approach to test the null hypothesis using a significance level of 0.05.