So in group 1 we had a total of 120 people and group 2 we had a total of 30 plus 110 is a 140 people and the placebo group, that is the group that just got the sugar pill, we had a total of 120 people and we can also tabulate the total number of people that got sick so thats 20 plus 30 that is 50 plus 30 is 80 so that is the total column right over here and the total people that didnt get sick over here is 100 and 110 is 210 plus 90 is 300 ant the total people here are 380 both this column and this row should add up to 380. so with this out of the way lets think about how we can use this information in the contingency table and our knowledge of the chi square distribution to come up with some conclusion. so lets come up with some null hypothesis. so our null hypothesis is that the herbs do nothing. the herbs do nothing.do nothing. and we have our alternative hypothesis that the herbs do something. herbs do something. notice i dont even care whether they actually improve. 