An automobile manufacturer claims that its car has a 37.4 miles/gallon (mpg) rating. an independent testing firm has been contracted to test the mpg for this car since it is believed that the car has an incorrect manufacturer's mpg rating. after testing 220 cars, they found a mean mpg of 37.1. assume the standard deviation is known to be 1.9. a level of significance of 0.01 will be used. make a decision to reject or fail to reject the null hypothesis. make a decision.