A student at a four-year college claims that mean enrollment at four-year colleges is higher than at two-year colleges in the United States. Two surveys are conducted. Of the 35 four-year colleges surveyed, the mean enrollment was 6,583 with a standard deviation of 469. Of the 35 two-year colleges surveyed, the mean enrollment was 6,333 with a standard deviation of 545. Test the student's claim at the 0.05 significance level. Preliminary: a. Is it safe to assume that nAyr $ 5% of all students enrolled at a 4-year college in the Unites States and n2yr