I realize you can transform the data in many ways, but I really can't find a method to solve this particular scenario anywhere online: Suppose you are given the mean and standard deviation of a set of data. Further suppose you take away (get rid of) "x" elements in the original data set, and now you're given the new mean. Is it possible to find the new standard deviation? It seems like it's something very simple, but I can't seem to come up with a solution. If it is indeed possible, how would I go about doing this? Numbers aren't important, but perhaps a numerical example to illustrate what I'm asking: A set of data has a mean of 20 and a standard deviation of 2. Suppose you take four elements from the set of data, and the new mean is now 50. What is the new standard deviation?