1. When people smoke, the nicotine they absorb is converted to cotinine, which can be measured. A sample of 40 smokers has a mean cotinine level of 172.5. Assume is known to be 119.5. [8 points] a) Find a 90% confidence interval estimate of the mean cotinine level of all smokers. Show all your work. b) Use a 0.01 significance level to test the claim that the mean cotinine level of all smokers is equal to 200.0