Why use prune function

[Porkins]

I just did an example in Actex where it created a tree using rpart. They then used cptable to find out which CP to use (after taking into account the one standard deviation rule) do get the correct tree to use. They then used prune and entered the desired CP to get a new tree.

Since we had to go through the trouble of figuring out the “best” CP and also how many terminal nodes there are couldn’t we just use rpart again but enter the correct CP and maxdepth arguments?

Is this just user preference or is there a reason to use prune and not rpart and the correct arguments?

 

[SamCastillo]

Hi Porkins,

Great question about decision trees that touches upon the way that you run code.  This can have a big impact on your exam report.  Here’s a screencast explanation.

Best regards,

Sam Castillo

Course Instructor at ExamPA.net

[Porkins]

Thank you for the very detailed and concise response. I appreciate it.

[Author]

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