That calculation was done by using the population (size of the deck), number of successes in the population (amount of mana sources), and the sample size, which is the number of cards youve drawn from the deck by the time you reach the target turn
He has a historical knowledge of games that I've seen rivaled by only a few people (Richard and Skaff Elias, by the way, have actually taught a college class on the history of games) and a wonderful intuitive sense of how game design works
Pokemons M6 Storm Emeralda (shipping on or after August 5, at 18,50020,000 per box at the time of writing) and One Pieces OP-17 (August 22 release) are current examples: launch-window quantity depends on what suppliers are actually allocated, and launch pricing can carry a premium that settles as reprint supply arrives
But since the Ultra Boost and Ultra Boost ST can be confusing choices, we felt that we owe to you to present a comparison