[Script Info]
Title:
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.60,0:00:01.94,Default,,0000,0000,0000,,Now let's do an example.
Dialogue: 0,0:00:01.94,0:00:06.74,Default,,0000,0000,0000,,So here's your reminder of the formula and suppose this is my data.
Dialogue: 0,0:00:06.74,0:00:11.04,Default,,0000,0000,0000,,I have four data points and for each data point I have three features,
Dialogue: 0,0:00:11.04,0:00:17.57,Default,,0000,0000,0000,,the grade of the train, the bumpiness, whether there's a speed limit,
Dialogue: 0,0:00:17.57,0:00:20.71,Default,,0000,0000,0000,,and then the speed that the car goes.
Dialogue: 0,0:00:21.95,0:00:23.44,Default,,0000,0000,0000,,And i'm just making up some data here.
Dialogue: 0,0:00:23.44,0:00:26.89,Default,,0000,0000,0000,,So let's start out at the top of the decision tree here.
Dialogue: 0,0:00:26.89,0:00:31.96,Default,,0000,0000,0000,,So I have two slow examples and two fast examples.
Dialogue: 0,0:00:31.96,0:00:36.20,Default,,0000,0000,0000,,Slow, slow, fast, fast.
Dialogue: 0,0:00:36.20,0:00:39.20,Default,,0000,0000,0000,,So the first question is, what's the entropy of this node?
Dialogue: 0,0:00:40.47,0:00:42.59,Default,,0000,0000,0000,,So let's do this piece by piece.
Dialogue: 0,0:00:42.59,0:00:46.88,Default,,0000,0000,0000,,How many of the examples in this node are slow?
Dialogue: 0,0:00:46.88,0:00:47.81,Default,,0000,0000,0000,,Write your answer here.