In a survey of 1430 undergraduate students, 1087 reported that they had one or more credit cards.
a. Provide a 90% confidence interval for the proportion of all college students who have at least one credit card.
b. Provide a 95% confidence interval for the proportion of all college students who have at least one credit card.
c. Assuming all else held constant, as the confidence level increases does the confidence interval get wider, narrower, or stay the same?