minor addition
the standard deviation is a measure of the amount of variation or dispersion of a set of values. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out over a wider range
the 68–95–99.7 rule, also known as the empirical rule, is a shorthand used to remember the percentage of values that lie within a band around the mean. more precisely, 68.27%, 95.45% and 99.73% of the values lie within one, two and three standard deviations of the mean, respectively
All the above are the basics of the Bollinger Bands, where build-in BB displays the area of two standard deviations of the mean.
This update will display all three areas
1- From mean to one standard deviations of the mean, background no color filled
2- Area between one and two standard deviations of the mean, background colored
3- Area between two and three standard deviations of the mean, background colored with different color