Imagine an automobile company looking for additives that might increase gas mileage. As a pilot study, they send 30 cars fueled with a new additive on a road trip from Boston to Los Angeles. Without the additive, those cars are known to average 25.0mpg with a standard deviation of 2.4 mpg. Suppose it turns out that the thirty cars averaged 26.3 mpg with the additive. What should the company conclude? Is the additive effective? Let α=0.01. Use three methods: the p-value , the critical value approach and the confidence Interval method a) b) Find the power of the test when u is actually (i) 25.750 (ii) 268 (iii) 28 What effect does increasing the distance between the true value of μ and hypothesized value μ-25 c) d) e) Find the power of the test when μ is actually 25.750 and n-100. What effect does increasing the sample size have on the power of the test? Find the power of the test when μ is actually 25.750 and n-30. What effect does increasing the sample size have on the power of the test? Use α-0.05 and α-0.1 What would be the effect on power when μ įs actually 25.750 ( n=30, α=0.01) ifơ could be reduced from 2.4 mpg b 1.2 mpg?
