Warning: more than you ever really wanted to know!
The forrmula details are covered in many old CCP dev blogs.
The notable ones being for Crius (when industry was overhauled) and Phoebe (when invention was overhauled). I can’t remember if there have been major industry changes since.
https://forums-archive.eveonline.com/message/5345680/#post5345680
https://forums-archive.eveonline.com/message/6629596/#post6629596
There are various posts by Steve Ronuken and Zifrian to search for that explain the formula stuff not documented in the dev blogs.