Example 2: A pit crew claims that its mean pit stop time (for 4 new tires and fuel) during an auto race is less than 13 seconds. A random sample of 32 pit stop times has a sample mean of 12.9 seconds and a standard deviation of 0.19 second. Is there enough evidence to support the claim of the pit crew at a = 0.01? 1: Ho: 2: H1: 3: a = 4: Xbar = 5. s = 6: z = 7. P-value = Decision and Interpretation: 'l.Suppose that an automobile manufacturer advertises that its new hybrid car has mean gas mileage of 50 miles per gallon. You take a simple random sample of n = 30 hybrid vehicles and test their gas mileage. You find that in this sample, the average is xbar= 47 miles per gallon with a standard deviation of s = 5.5 miles per gallon. Does this indicate that the advertiser's statement is true or false? 1: Ho: 2: H1: 3: a = 41Xbar= 5. s = 6:2 = 7. P-value = Decision and Interpretation: 3.A manufacturer of sprinkler systems designed for fire protection claims that the average activating temperature is at least 135.F. To test this claim, you randomly select a sample of 32 systems and find the mean activation temperature to be 133.F with a standard deviation of 3:3.F. At a = 0.10, do you have enough evidence to reject the manufacturer's claim? 1: Ho : 2: H1: 3: a = 4: Xbar = 5. s = 6: Z = 7. P-value = Decision and Interpretation