A few points here: a) “Calculator saves time. Time=chance of a higher score on the exam. Get used to the calculator, it’ll help you A LOT on the exam.” Yuck. Learn how to use your calculator but what will save you time on the exam is learning the material. Time pressure is not that important. Calculators suck. Other than the CFA exam, I haven’t owned a calculator since high school. b) cpk’s trick - This trick works, sort-of. It doesn’t work if the numbers were like 37.22%. This is a trick you should use only if you don’t have to. c) Using your calculator’s automatic data analysis functions to get population values really muddies up the distinction between the two in ways that are likely to be more damaging than helpful. If you do this, make absolutely sure you know what you are doing and know what the relationship is, say, between the cpk-claculated std. dev and the std. dev. you would get from sampling data from the distribution. Knowing that distinction is what is going to help you pass the exam (btw - I would bet my life against $10 that cpk knows the difference). d) “I know this formula but if you are not given the st deviations or correlation??” Calculating population correlation requires that you are given bivariate data with probabilities. Of course, since the correlation coefficient is not very relevant for data that is not bivariate normal what you calculate is pretty meaningless. That means they would have to give you a long question that takes up lots of space to write whose answer is meaningless. Possible, but not very likely.