In finding a confidence interval for a random sample of 30 students GPAs, one interval was (2.60, 3.20) and the other was (2.65, 3.15).
a. One of them is a 95% interval and one is a 90% interval. Which is which, and how do you know?
b. If we used a larger sample size (n = 120 instead of n = 30), would the 95% interval be wider or narrower than the one reported here?