1. An antipollution device for cars is claimed to have an average effectiveness of exactly 546. Based on a test of 20 such devices you find that X‾ = 565. Assuming normality and that σ = 40, would you rule out the claim with a Type I error probability of .05?
2. Comment on the relative merits of using a .95 confidence interval for addressing the effectiveness of the antipollution device in Exercise.
Exercise
An antipollution device for cars is claimed to have an average effectiveness of exactly 546. Based on a test of 20 such devices you find that X‾ = 565. Assuming normality and that σ = 40, would you rule out the claim with a Type I error probability of .05?