Replaced Boston dataset with California in Catboost tutorial

[owenlamont]

Overview

Description of the changes proposed in this pull request:

This is another step towards completing issue 2322.

Checklist

• All pre-commit checks pass.
• Unit tests added (if fixing a bug or adding a new feature)

[thatlittleboy]

Thanks @owenlamont for the contribution.

It's a little hard to review notebooks on GH, I'll use images to get my point across:

• red box: Typo, should be AveRooms.
• pink box: The coloring is by MedInc, not RAD.

• there isn't an LSTAT feature in California, you can change it to MedInc.

[thatlittleboy]

see comment above.

[owenlamont]

Cheers, yeah I should've been aware the features would be different, I'll get onto those updates.

[owenlamont]

I've tweaked the text, I'm struggling a little to give a reasonable interpretation of the dependence plot description, would welcome feedback on that (maybe there's a better feature I should have chosen for the dependence plot other than AveRooms that would have given an easier to interpret plot).

[thatlittleboy]

@owenlamont I went round all the variables and didn't really find any variables' dependence plot to be particularly illustrative / easy to interpret.

What do you think about this instead? It's the best I could come up with.

I'm seeing that:

• at lower MedInc (let's say <=4), the HouseAge doesn't have a strong impact on the house prices (or at least, the dependence relationship isn't that clear tome)
• at higher MedInc, older houses tend to have higher prices (if we squint a little, we can generally see that the red dots are higher than the blue dots, for the same MedInc).

[owenlamont]

Thanks for the feedback @thatlittleboy - I've used your example and tweaked your phrasing a little for the description. I hope that looks okay:

I also noticed the old Boston House Price example is used on the main README too... guess at some point that should be changed. I think we might want an entirely different dataset we can tell a nice story with using SHAP for that though.

[dsgibbons]

I also noticed the old Boston House Price example is used on the main README too... guess at some point that should be changed. I think we might want an entirely different dataset we can tell a nice story with using SHAP for that though.

@owenlamont this has been fixed by #3200. Happy for another dataset to be used if it tells a more compelling story.

[owenlamont]

Yeah... I'm sure there must be a better dataset for this example. I'm afraid I'm a bit time poor and have some other priorities so I don't think I'll go looking for it myself but happy to try and keep contributing in small ways.

[thatlittleboy]

Thanks @owenlamont for the contribution, Sorry it took so long to get back to you. I took the liberty to clean up a couple more things, like using the new plots api (e.g. shap.plots.force instead of shap.force_plot) where possible.

[owenlamont]

Thanks for finishing it off @thatlittleboy !