Sitting down this week and having a look at army lists for tournaments in 2024 and was trying to work out "what is the best unit to use?" and "which unit is most cost effective?" As such I started looking at probabilities and math to try and assist in squad selection. Fortunately, someone has already done some of the hard work so I didn't need to tax my A level math too much!
This article on Goonhammer is appropriate across the board for wargamers, so when planning your gaming have a read and I hope it helps: https://www.goonhammer.com/getting-better-at-warhammer-40000-understanding-probability/