4. The average weight of the first year students is 52.8 kg, whereas the average weight of the third year students is 56.0 kg as shown in the table below. Assuming that the data follows an approximate normal distribution, test the hypothesis that the average weight of third year students is higher than the average weight of the first year students at 5% significance level. First Year Third Year Students Students 50 52 52 54 51 58 49 59 56 55 54 53 51 57 57 55 53 61 55 (10 marks)