Five years ago, a county lottery official conducted a very extensive (and expensive) study to determine the average age of lottery players in the county. From the data, he estimated the true age to be about 50 years. Five years later, the lottery official wants to know if the average age is now different from 50 years. He plans to conduct a smaller (and less expensive) survey of lottery players. From a random sample of 81 players from the county, the average age is 48.7 years with a standard deviation of 8.5 years. (a) is there convincing evidence at the a = 0.05 significance level that the present-day average age of all lottery players in the county is different from 50 years.
(b) Referring to your conclusion in part fa), what type of error may have been made? Describe the error in the context of this study.