Standard deviation
A standard deviation is a (slightly messy) statistical calculation that results in a positive number that measures how much the possible results differ from the average result. For those of you who want to know more, it is square root of the weighted averageA calculation using all of the observations of a variable with each observation being assigned a weight. The weight is the relative importance of that observation. Each observation is multiplied b... More of the squares of the differences between each possible result and the mean, where the weights are the probabilities of the various possible results.
I am also a retired property-casualty actuaryA professional who assesses and manages the risks of financial investments, insurance policies and other potentially risky ventures. Source: www.investopedia.com/terms/a/actuary.asp More (someone who works with the math and statistics related to insurance). I spent a significant portion of my career building statistical models of all of the financial risks of an insurance company and interpreting their findings to help senior management make better financial decisions. I retired in my late 50’s, which one of my daughter’s friends thought clearly qualified me to write this blog. Read more about Susie Q