1. The data below are the electricity consumptions in kilowatt-hours per month from ten houses and the areas in square feet of those houses:
(a) Plot the data with KW on vertical axis.
(b) Write out the nonlinear equation form for a linear-quadratic segmented polynomial model. (KW is the response)
(c) To the best of your abilities, provide educated guesses for the starting values for the parameters.
(d) Fit the model and provide all parameter estimates and standard error, including the "cut-off" point θ between the two lines. Write out the linear and the quadratic equations explicitly.
2. A repeated measures experiment was performed to decide which of the two textbooks the class should use in the future. The data are given below.
(a) Should one fit a GEE or conditional GLMM model, explain which one should be used and why.
(b) What correlation structure should be used, feel free to explore more options than the one covered in class.
(c) Write conclusions on your findings.