10: ANCOVA Part II

Overview Section

In this lesson, we will extend our ANCOVA to model quantitative predictors with higher-order polynomials by utilizing orthogonal polynomial coding. Fitting a polynomial to express the impact of the quantitative predictor on the response is also called trend analysis, and helps to evaluate the separate contributions of linear and nonlinear components of the polynomial. The examples discussed will illustrate how software can be used to fit higher-order polynomials within an ANCOVA model.


Upon completion of this lesson, you should be able to:

  • Use ANCOVA to analyze experiments that require polynomial modeling for quantitative predictors.
  • Test hypotheses for treatment effects on polynomial coefficients.