NinjaScript > Language Reference > Indicator Methods >
The r-squared indicator calculates how well the price approximates a linear regression line. The indicator gets its name from the calculation, which is, the square of the correlation coefficient (referred to in mathematics by the Greek letter rho, or r). The range of the r-squared is from zero to one.
... Courtesy of FMLabs
double; Accessing this method via an index value [int barsAgo] returns the indicator value of the referenced bar.
You can view this indicator method source code by selecting the menu Tools > Edit NinjaScript > Indicator within the NinjaTrader Control Center window.