To compare freshmen's knowledge of history, samples of 50 freshmen from each of two universities were given a special test. If those from the first university have an average score of 67.4 with a standard deviation of 5.0, while those from the second university have an average score of 62.8 with a standard deviation of 4.6, test at the 0.05 level of significance whether the difference between the means of the samples is significant.