is $r2 valid in nonlinear models is $r$ valid in a nonlinear model is $r2 valid? how is coefficient of determination a nonlinear is coefficient of determination valid in a nonlinear model is $r2 valid in a nonlinear model? is $r2 valid in a nonlinear model is r2 valid in a nonlinear model is $r2$ a valid value in an integer model? is $r2 valid which model is r2 valid in is coefficient of determination valid if no coefficient is valid in a nonlinear model why is coefficient of determination valid in nonlinear models? is $r2 valid in a nonlinear model? is r2 valid what is the coefficient of determination of the linear model? is $R2 valid are coefficients of determination valid in a nonlinear model? is the coefficient determination valid in a trig nonlinear model?