I have to analyse students marks from a particular module. The module is split into sub components: Assignments and Exams (which I will call components), for each Module the number of Assignments and Exams vary so I dont know how many components there are.<BR><BR>I have to work out the standard deviation for the set of student marks in a component, but due to the way the data is stored I have to put the marks into a 2D Array.. 1st Dimension the component number, and the second the mark for that individual student on that component. (Confused?)<BR><BR>So I now have a 2D Array which holds all the marks for the whole module: eg if 3 students and 2 components the array looks like this:<BR>(1,45)(1,56)(1,34)(2,65)(2,43)(2,74)<BR>< BR>Now I have to get the standard deviation for each component. How can I do it??<BR><BR>Sorry for the long explanation.. but any help would be gratefully recieved.