Suppose you have two random samples of the profit margins obtained by two stock traders, Trader A and Trader B. The first data set consists of 18 data, and the second has 21. I want to check if there is association between the variables "type of trader" (values A or B) and "profit margin". In words, I need to find out if the choice of trader influences the profit margin obtained. Since the observations are not paired and, after all, the numbers of observations are distinct, I cannot use the linear correlation coefficient formula. I know there is a formula to verify if a nominal (discrete) variable and a continuous varible are associated. I also know it involves the means and standard deviations of both data sets. I have been told, too, that it gives a result ranging from 0 to 1 and that, the closer it is to 1, the stroger is the association. The trouble is I missed the class about the formula and it has proven really hard to find it on the web, since I don't know its name. So I would really appreciate if you guys could write it down for me. I need it as soon as possible and I can't ask my teacher right now; so I really need your help. If the data sets are needed, I can provide them. But I don't think they're necessary, now that it's only the formula what I need. I already know how to solve the problem. Thanks in advance, hellofolks.