Students in a statistics class take a random sample of 100 students at their college and record how many units each student is enrolled in. The students compute a 90% confidence interval for the mean number of units for students at their college and get (11.93, 12.47).

Next, the students calculate a 95% confidence interval. As the confidence level increases, which of the following will happen to the interval width?

a) Decrease
b) Increase
c) Stay the same