1. A researcher wishes to estimate, with 99% confidence, the percentage of adults who support abolishing the penny. His estimate must be accurate within 4% of the true proportion.

a) Find the minimum sample size needed, using a prior study that found that 26% of the respondents sad they support abolishing the penny.

b) No preliminary estimate is available. Find the minimum sample size needed.

(Round to the nearest whole number.)

2. Find the margin of error for the given values of c, s, and n.

c= 0.95, s = 4, n = 14

(Round to one decimal place.)

3. Find the critical value t c for the confidence level c= 0.95 and sample size n= 10

(Round to the nearest thousandth.)