Mathematics

Solomon Hanson

22 December, 17:52

Suppose we want a 90% confidence interval for the average amount spent on

entertainment (movies, concerts, dates, etc.) by Freshman in their first semester at a

large university. The interval is to have a margin of error of $2, and the amount spent

has a normal distribution with a standard deviation s = $30. The number of

observations required is closest to

A) 25.

B) 30.

C) 609.

D) 865.