Chapter 8, Problem 4PE

4. Dynamic regression (adapted from Q10.4 in Hyndman & Athanasopoulos) This exercise concerns aus_accommodation: the total quarterly takings from accommodation and the room occupancy level for hotels, motels, and guest houses in Australia, between January 1998 and June 2016. Total quarterly takings are in millions of Australian dollars. a. Perform inflation adjustment for Takings (using the CPI column), creating a new column in the tsibble called Adj Takings. b. For each state, fit a dynamic regression model of Adj Takings with seasonal dummy variables, a piecewise linear time trend with one knot at 2008 Q1, and ARIMA errors. c. What model was fitted for the state of Victoria? Does the time series exhibit constant seasonality? d. Check that the residuals of the model in c) look like white noise.

ce- 216 Answer the following, using the figures and tables from the age versus bone loss data in 2010 Questions 2 and 12: a. For what ages is it reasonable to use the regression line to predict bone loss? b. Interpret the slope in the context of this wolf X problem. y min ball bas oft c. Using the data from the study, can you say that age causes bone loss? srls to sqota bri vo X 1931s aqsini-Y ST.0 0 Isups Iq nsalst ever tom vam noboslios tsb a ti segood insvla villemari aixs-Yedi

120 110 110 100 90 80 Total Score Scatterplot of Total Score vs. Putts grit bas 70- 20 25 30 35 40 45 50 Putts