Question: A confidence interval estimate is determined from the weights of an SRS (simple random sample) of n students. Which of the following will result in a SMALLER confidence interval width?

I. A smaller sample size
II. A smaller sample standard deviation
III. A smaller confidence level

a) I only
b) II only
c) III only
d) II and III
e) I and III  Edit

Answer: e) I and III
Because , margin of error=sigma/sqrt(n)*z_c

if n small and z_c large the margin of error large , so interval (x bar -me, x bar +me) will be large.  Edit