Odds of a hundo in raids
Have over 1200 legendary raids, seen 3 hundoes, caught 2 of them, moltres and mewtwo, lost an entei a long time ago.
Whats the odds of encountering a hundo lvl 5?
Mine has been 1:400 so far. Is there a statistics for this somewhere?
Your assumption is that each stat and each number has equal probability to be drawn. While I don't know if it's true, but personally I doubt it.
Formally you can do a hypothesis testing, with null hypothesis being, say, rate of hundo from legendary raid is 1 out 216. But only based on one player's experience may not give very confident result.
Without looking at whatever is used for determining IV's of a raid boss in the catch screen, I'd be surprised if some part of the number generation favored particular stat spreads over another. I think for all intents and purposes it's safe to say you're as likely to roll a hundo as you are a 12/14/13, 13/10/11, 10/10/10, or any other IV combination where each stat is between 10-15.
"Your assumption is that each stat and each number has equal probability to be drawn. While I don't know if it's true, but personally I doubt it."
People at the sylph road and other research sites have looked at this question, and have come to the conclusion that the statistics are linearly distributed within the specified range to within statistical error, every time. Individual results may vary, but take a huge data sample, and one finds that it's simple linear probabilities.
Since your original question was already answered we might as well share what other odds are:
Weather boosted hundo (IV floor of 4): 1:1728
Good friends trade (IV floor of 1): 1:3375
Great friends trade (IV floor of 2): 1:2744
Ultra friends trade (IV floor of 3): 1: 2197
Best friends trade (IV floor of 5): 1:1331
Lucky trade (IV floor of 12(!)): 1:64
While it's still not in your favor much, the trading odds increase significantly from good to best. Having said that I've yet to roll a lucky hundo despite rolling a non-lucky hundo from a best friend trade.