I am trying to train one such sample.
X= [ [1 2]
y = [5, 5 , 8]
And I am trying try to use the code below to train the sample.
plot_tree(reg,num_trees = 0)
Then i got two trees below.
Then I got into confusion when I entered a test sample X_test=[1,2], because
reg.predict(X_test) #print score = 4.875
Score with the trees structure above： 0.25 + 4.125 = 4.375
Why? Is there anything wrong with my operation?