Sample size and the width of confidence intervals_______________.

a. have no relationship to each other. 

b. increase at different rates: sample size increases faster than interval width. 

c. increase at different rates: sample size increases more slowly than interval width. 

d. increase at the same rate. 

To construct the narrowest possible confidence intervals, use __________. 

a. small samples 

b. an unbiased statistic 

c. the least efficient estimator 

d. large samples