what does r2 mean? what is the r value for n what is r2 why is there a r2 value? why is there a nan value in r what is the purpose of r2 in src++ why is lm greater nan or nan why is there an r2 value what is r2 x why is there an r2 value? why is there r2 mean in r what is nan in r why is an r2 value why is r2 greater than nan why is there a r2 value what is nan in r why is there an r2 value, and what is determining it, when lm has no variance in the predicted value? why is there an r2 value why is there an r ra2 value when lm has no variance in the predicted value? what is the nan value of r a function