Standard deviation is a metric that shows the variability of a security’s returns over time. It can be used to gauge volatility based on past performance and compare a future return to past returns.

The normal distribution is the probability distribution that plots all of its values along a symmetrical bell curve, with the highest probabilities centered around the mean value and tapering out ...

IQ 100 is the benchmark value set as the "average" in most intelligence tests. In terms of ranking, it is exactly in the middle of the group, and in terms of percentile, it corresponds to the top 50%.