when you call a step function, r returns what model will r generate what is the function in r for mammals r generates a stepwise model whose return is a negative. cv.glm returns nan what function returns nan what does cv.glm mean what is the nan in r what is the function nan in r cv.glm return nan how to cross validate multiple linear regression models what is the function to cross validate a stepwise model r cv generates nan what function returns nan r generates nan for stepwise crossvalidation does r generate a stepwise model what is cv.glm in r which function is nan r generates nan what is mammals glm