Description: function T.INV(1,n) should return error Actual Results: value Expected Results: error Reproducible: Always User Profile Reset: No Additional Info: User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:51.0) Gecko/20100101 Firefox/51.0
Winfried confirmed.
The Microsoft 'specification' (https://support.office.com/en-us/article/T-INV-function-2908272b-4e61-4942-9df9-a25fec9b0e2e) is incorrect, as the constraints for p are 0 < p < 1. (The actual behaviour of Excel is correct and not as stated in the 'specification'.) The mathematic rule is "For all continuous distributions, the ICDF exists and is unique if 0 < p < 1." (ICDF - inverse cumulative distribution function). A p of 0 is reached at minus infinity and a p of 1 is reached at plus infinity, i.o.w. there is no concrete value X for which the cumulative left tailed t-distribution probability is 0 or 1.
Winfried Donkers committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=76198c537fa7595b94b2f930081bf7f6ec966dbe tdf#106049 Apply proper constraints for Calc function T.INV. It will be available in 5.4.0. The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.