So this could right here just be a sugar pill. And a very small amount of sugar, so it really can't affect their actual likelihood of getting the flu. So over here we have a table, and this is actually called a contingency table. And it has on it, in each group, the number that got sick, the number that didn't get sick. And so we also can, from this, calculate the total number. So in group 1, we had a total of 120 people. In group 2, we had a total of 30 plus 110 is 140 people.