A group of 5 patients treated with medicine A is of weight 42, 39, 38, 60 and 41 kg. Second group of 7 patients from the same hospital treated with medicine B is of weight 38, 42, 56, 64, 68, 69 and 62 kg. Test whether the average weight of patients treated with medicine A is less than that patients treated with medicine B at 5% level of significance?