ARKA-Z-Score

This Indicator is based on Mr. Dan Valcu ideas.
The author of this article is Veronica Valcu.
The z-score (z) for a data item x measures the distance (in standard deviations StdDev) and direction
of the item from its mean (U):
z = (x-StdDev) / U
A value of zero indicates that the data item x is equal to the mean U, while
positive or negative values show that the data item is above (x>U) or below
(x Values of +2 and -2 show that the data item is two standard deviations
above or below the chosen mean, respectively, and over 95.5% of all data
items are contained within these two horizontal references.

Based on the article and ideas about the z-score concept we can use it to get more confidence where we want to be sure this is an oversold or overbought zone.
The indicator draws two levels on 2 and -2. Z-Score color comes red when it goes above 2, and the color changes to green when it goes below the -2 level. The Z-Score color which value is between 2 & -2 is gray.