This summarises a tree fit to the last 25 years of Australian tourism data modeling the difference in patterns between Cairns and Melbourne. Only holiday travel is examined, and the four variables used are Q1, Q2, Q3, Q4 which are quarters in the year. Each series was standardised on itself, so values represent proportion of travel for holidays relative to other types of travel to the city in each quarter of each year. We are curious to determine whether holiday travel tends to be in different seasons in the two locations.

n= 50 
node), split, n, loss, yval, (yprob)
      * denotes terminal node
 1) root 50 25 Cairns (0.500 0.500)  
   2) Q3>=0.43 24  1 Cairns (0.958 0.042) *
   3) Q3< 0.43 26  2 Melbourne (0.077 0.923)  
     6) Q3>=0.39 7  2 Melbourne (0.286 0.714)  
      12) Q2< 0.32 2  0 Cairns (1.000 0.000) *
      13) Q2>=0.32 5  0 Melbourne (0.000 1.000) *
     7) Q3< 0.39 19  0 Melbourne (0.000 1.000) *

1. (1pt) How many terminal nodes in the tree?
2. (1pt) How many of the four variables are used in the model?
3. (1pt) Which variable would be considered to be the most important?
4. (1pt) Which terminal nodes are pure nodes (having only one class)?
5. (1pt) How many observations are there at node 7?
6. (2pts) Based on this model, how would you describe the differences in holiday travel between Melbourne and Cairns?