So like I said after tracking 60ish eggs last week
Many more previously rare mons aren't rare anymore. I for one really like this move as eggs had become extremely boring prior to the gen 2 release. It was also preliminarily found that biomes don't influence egg percentages.
My advice from that thread still stands: if you are lacking a Blissey or Dragonite (etc) this is a good time to cycle some eggs with extra incubators. I could see these numbers getting nerfed or otherwise negatively adjusted.
https://www.reddit.com/r/TheSilphRoad
Answers
They say the data isn't 100% for sure but they found no correlation between biome and egg draw. Their sample size and professional methods make it fair to say that any major connection to certain eggs gained in certain biomes do not play a role in hatch chances although further research would be warranted. That is extremely hard to track accurately though.
To simplify that in regards to Dratini if you get a 10K egg no matter where you are you should have about a 21% chance of it being a Dratini now per their numbers.
To summarize the percentages for 10K eggs:
Aerodactyl 2.58% (1 in 40)
Chansey 5.09% (1 in 20)
Dratini 20.52% (1 in 5)
Gligar 10.26% (1 in 10)
Lapras 2.58% (1 in 40)
Larvitar 10.26% (1 in 10)
Mantine 10.26% (1 in 10)
Mareep 5.09% (1 in 20)
Miltank 2.58% (1 in 40)
Pineco 20.52% (1 in 5)
Skamory 2.58% (1 in 40)
Snorlax 2.58% (1 in 40)
Sudowoodo 5.09% (1 in 20)
However these numbers are kind of misleading since the commonness of Dratini and Pineco (among others) make it much more likely that you get a 10K egg when you spin a pokestop than prior to the update.
Pineco 20.52% (1 in 5)
Strange.... where do these fractions of percents come from? My head and my calculator tell exactly 20% for 1 in 5.
What do me 4 valid digits (2 of them obviously wrong) for a statistics of 40 hatched eggs tell? I would dare giving 3 digits if i have a sample of 1000 Eggs, 4 digits in a sample of 10.000 Eggs at least.
p.s. 63,468264% of all statistics imply an accuracy that is not justified by data base.
I'm not sure that I understand your point. These numbers are not your chances of getting any certain Pokemon when you spin a stop. They are the percentages of your chances of having the 10K egg that you already have being one of the Pokemon listed above. those are the ones available and their percentages add up to 99.99 percent when combined. The numbers are based on the post gen 2 data set of total 10K eggs and percentage of resulting pokemon. I think the post gen 2 total sourced count was around 2500 reported hatchings. I think that their strengthening of the total tier system (1:2:4:8) as it applies to rarity was based on other research with less control although blind to the controlled findings which sourced a reported 133,547 eggs just to strengthen the tier data that this was all based on. The overall idea is that Pokemon moved in tiers of rarity without changing their egg type which will make rarity tracking in the future much easier to follow if around 150K eggs is a big enough sample size for you to believe in rarity tiers and get around the two decimal places it causes.
To explain how those numbers were found (credit Sangheilioz on Reddit):
"I calculated the percent chance of getting a certain type of egg (2, 5, or 10 KM) by adding up the chances of getting any Pokemon that comes from that type of egg. I got the individual Pokemon's chances by multiplying 1 by their rarity modifier (common * 8, uncommon * 4, rare * 2, ultra-rare * 1) individually. From there, it was simple enough to divide the chance of getting each particular pokemon by the chance of getting that type of egg. (And for those worried about my sanity, I did it all in an excel spreadsheet using formulas. I'm not crazy enough to do all of this by hand!)"
It is also no coincidence that folks that post 68,954.896743% of these type comments did not read the linked source material and quibble with those that brought it instead of someone who just linked it for your convenience.
I finally hatched a dratini yesterday...after walking 360kms - but it gave me a good IV one to finally get a Dragonite.
I have not seen a single Pineco yet, but I have got 3 Chansey (as if I need it), and so many Gligar.
Larvitar I have done well with, as well as Mareep - along with a few dex entries for Gen2.
I wish my dratini rate was 1 in 5...but my Mareep Larvitar and Chansey rate is far better than the listing.
I guess some people get more than others, to help keep the averages consistent, over a larger dataset.
1 single players experience is not going to be consistent for every single person.
Not everyone will be getting this type of spread...but it will balance out over a larger 'n'
I think there is a tie to biomes but it's so hard to properly nail down in the research that it won't come out until further testing. In terms of Dratini since the thought is that they often show at "man made water sources" a single stop may source something usually insignificant like (I dunno) a water tower which may not effect spawns but perhaps Eggs source biomes a little differently.
