I am working with a list of 15 - 20 whole numbers and calculating the mean,
one std dev above and one std dev below. My data consists of many 0 values
as well as high numbers over 100. My std dev -1 calculation is coming out
negative. I would expect a large variation but not a negative std dev.
Since I understand std dev is the square root of a square, I have to assume
operator error. Can someone clarify what may be my error, not seeing my
data, or confirming that std dev can be negative? Thanks for your help.