1) The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan. A random sample of 12 employees in 2004 reveals the following family dental expenses (in dollars): 115, 370, 250, 93, 540, 225, 177, 425, 318, 182, 275, and 228. The sample mean is ______________

Construct a 95% confidence interval estimate of the mean family dental expenses for all employees of this corporation. The upper boundary/limit is______________ and the lower boundary/limit is_________________1 . (Please keep two decimal points.)

2)Of type I and type II error, which is traditionally regarded as more serious?

• A. Type I

• B. Type II

• C. Type I and Type II are equally serious

• D. Neither Type I or Type II is serious and both can be avoided