I majored in stats so I can explain it. In this situation having a 1/35 probability of finding a deer just means you will find a deer close to 1 out of every 35 tries if you use many, many NMT. So if you used 35,000 NMT, you'd find a deer close to 1000 times. But in small sample sizes (like using only 35 NMT), the outcomes are a lot more unpredictable. You have about a 64% chance of finding at least one deer in 35 tries, which is better than 50%, but you still have a greater than 1/3 probability of not finding a deer at all. You could get lucky and find more than one deer in those 35 tries as well. Over many, many tries you'll have hot streaks where you find many deer quickly and cold streaks where you don't find any deer at all for a long time, but those hot streaks and cold streaks will balance out so you find a deer close to once every 35 tries overall. Unfortunately, it's not realistic to get and use thousands of NMT, so you may end up getting screwed by bad luck because you're forced into a small sample size. The campsite is more reliable because it's rigged to avoid repeat villagers of the same personality, but if you're going for one species only, then there may not be much of a difference since the campsite doesn't have the favorable species roll mechanic.