what type of relationship is curvature terms in r why do you use quadratic in models why can't model selection be linear or quadratic is the quadratic term useful in model selection? why should i use a quadratic term in a model selection analysis how can i know if my model is modeled r without the quadratic term how do you use curvature terms why r does not include quadratic term in a model why is it important to use a quadratic term in mun if a model has a quadratic term, will it include the linear term in the model selection when to use the quadratic term for curve in r what is a linear term for curves why does r use linear terms when you do a continuous continuous model selection analysis with a continuous variable and categorical variables, you can expect that a quadratic term in the model selection statement is used. when do you use a curvature term can curve terms have a quadratic relationship why is linear term not necessary in models r does model selection need quadratic term what is the difference between a linear term and a quadratic term in r can r use only quadratic term