The reg function fits a multiple linear regression analysis
of one or more independent (exogenous) variables on a dependent(endogenous)
variable in a linear pattern along with testing the significance of
parameters. It is important that according to the type of data may produce some warning errors e.g., for dtsimp as:
Warning message: In summary.lm(mlreg): essentially perfect fit: summary may be unreliable.
This case is due to the intrinsic characteristics of data