Is there an inverse Chi Square formula - Same as Excel CHIINV function?

[Metabrit]

Hi,

I'm trying to migrate one of our analysis tools into an alteryx workflow and part of the analysis tool uses the CHIINV function in Excel.

Does anyone know of a way to do the CHIINV function from Excel in Alteryx formula tools?

[Metabrit]

@MarqueeCrew Do you guys have any solution to this? Love the formula addons you created and could do with you're help on a CHIINV function.

[MarqueeCrew]

My friend, @jdunkerley79 created the formula pack.  He's copied here to hear the request.

Cheers,

Mark

[Metabrit]

Thanks, I've just realised I also need to be able to do a TINV function as well (two-tailed inverse of the Student's t-distribution). 

[jdunkerley79]

Give me a weekend. Will add to the Abacus library and release.

[MarqueeCrew]

@jdunkerley79 == "SuperACE"

[Metabrit]

Awesome! Thanks a lot, I'll await the next release

[patrick_digan · Accepted solution]

@Metabrit If you have the predictive tools installed (http://downloads.alteryx.com/predictive.html if you're on 11.3 or http://downloads.alteryx.com/changes.html if you're on a previous version) you can use R functions like qchisq and qt. I put together a quick macro for the Inverse ChiSquared and Inverse T.

[Metabrit]

Thanks Patrick,

That's definitely a great solution! I'll use this macro until @jdunkerley79 adds the formulas to his bundle.

[jdunkerley79]

Added to the new version 1.3 release: https://github.com/jdunkerley/AlteryxFormulaAddOns/releases/latest

- TInv, TDist for the 2 tailed Student T

- ChiInv and ChiDist for the right hand of the Chi squared distribution

Both based on the Boost C++ library and tested against Excel's functions