3. Suppose we want a 95% confidence interval for the average amount spent on books by freshmen in their first year at college. The amount spent has a normal distribution with a standard deviation of...

3.

Suppose we want a 95% confidence interval for the average amount spent on books by freshmen in their first year at college. The amount spent has a normal distribution with a standard deviation of $27.

(a) How large should the sample be if the margin of error is to be less than $4?

(b) If we wanted a smaller margin of error, we would need a  sample. (Write ''LARGER'', ''SMALLER'' or ''SAME SIZE'')