An automobile manufacturer claims that their car has a 48.7 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the MPG for this car. After testing 9 cars they found a mean MPG of 49.1 with a standard deviation of 1.2 MPG. Is there sufficient evidence at the 0.05 level that the cars have an incorrect manufacturer's MPG rating? State the null and alternative hypotheses for the above scenario.