Based on a study in 2015, of all students enrolled at a large undergraduate university, 18% are seniors, 25% are juniors, 24% are sophomores, and 33% are freshmen. In 2020 a sample of 200 students taken from this university by the student senate to conduct a survey includes 48 seniors, 49 juniors, 56 sophomores, and 47 freshmen. Using the 2.5% significance level, test the null hypothesis against the alternative hypothesis that proportions of enrolled students in 2020 are different from those in 2015. a) State the null and the alternative hypothesis. What distribution will you use to find the critical values? b) Find the critical value and show on a picture the rejection and nonrejection regions. A/ c) Complete the table on your paper with values needed to calculate the test statistic. Category (response)