Answer Happy

Q5. [2+3+3] An automobile manufacturer has given its car a 45.5 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the actual MPG for this car since it is believed that the car has a lower MPG rating. After testing 150 cars, they found a mean MPG of 45.2. Assume the population standard deviation is known to be 1.3. A level of significance of 0.01 will be used. (a) Is it a left tailed or a right tailed or a two tailed test? (b) Compute the test statistic. (c) Make the decision to reject or fail to reject the null hypothesis. Q6. [2+3+3] An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 5.6 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 9 engines and the mean pressure was 5.9 pounds/square inch with a sample variance of 0.81. A level of significance of 0.05 will be used. (a) Is it a left tailed or a right tailed or a two tailed test? (b) Compute the test statistic. (c) Make the decision to reject or fail to reject the null hypothesis.