Question 1 An educator claims that the average salary of substitute teachers in school districts in Allegheny County, PA is less than $60 per day. A random sample of eight school districts is...

Question 1

An educator claims that the average salary of substitute teachers in school districts in Allegheny County, PA is less than $60 per day. A random sample of eight school districts is selected, and the daily average salary (in dollars) is $58.88 with a sample standard deviation of $5.08. Set alpha = 0.10 for this test. Is there enough evidence to support the educator’s claim?

Question 2

A tobacco company claims that its best-selling cigarettes contain less than 40mg of nicotine. This claim is tested at the 1% significance level by using the results of 15 randomly selected cigarettes. The mean is 42.6 mg and the standard deviation is 3.7mg. Evidence suggests that nicotine is normally distributed. Is there enough evidence from this study to support the claim of the tobacco company?

Question 3

A survey of 15 large U.S. cities finds that the average commute time one way is 25.4 minutes. A chamber of commerce executive feels that the commute in his city is less and wants to publicize this. He randomly selects 25 commuters and finds the average is 22.1 minutes with a standard deviation of 5.3 minutes. At alpha = 0.10, is he correct?