Questions 6

  1. Why does discrete explanatory variable should be recoded into dummy variables before being used in the model?
  2. Explain what we mean by dummy variable trap.
  3. Compare the use of contrasts in a model with standard way of recoding the discrete explanatory variable
  4. When do we talk about interactions between variables in linear model?
  5. Describe the ways a nonlinear dependence can be approximated with linear model.