Hello,how you can calculate an arithmetic return going from a negative number to a positive number or going from a high negative number to a low negative number? This is a topic of debate in my group right now. We have a number of returns from a project

$ (5.2) $ (2.3) $ (3.4) $ 0.2 $ 3.0 $ 6.0 $ 100 $

As you can see some are negative and some are positive. We want to be able to calculate for variance and standard deviation, but we are a bit confused.