State whether each of the following changes would make a confidence interval wider or narrower. (Assume that

Question:

State whether each of the following changes would make a confidence interval wider or narrower. (Assume that nothing else changes.)
a. Changing from a 95% level of confidence to a 90% level of confidence.
b. Changing from a sample size of 30 to a sample size of 20.
c. Changing from a standard deviation of 3 inches to a standard deviation of 2.5 inches.