Question

An automobile manufacturer claims that its jeep has a 59.8 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the MPG for this jeep since it is believed that the jeep has an incorrect manufacturer's MPG rating. After testing 160 jeeps, they found a mean MPG of 59.7. Assume the standard deviation is known to be 1.3. A level of significance of 0.02 will be used. Find the value of the test statistic. Round your answer to 2 decimal places. Enter the value of the test statistic.

Answer 1

this is the two tailed test .  

The null and alternative hypothesis is ,

H0 :   = 59.8

Ha :     59.58

Test statistic = z

= ( - ) / / n

= (59.7-59.8) / 1.3 / 160

= -0.97