I also couldnt successfully add any double-faced cards to my list, which might be by design given printing complications with DFCs
Let's start with the "Gamma Orb", from a set mostly known as "Gamma"
Target is reportedly so fed up with Pokemon Trading Card Game scalpers that it is taking unique measures to stop customers buying ridiculous amounts of product at a time
Where the binomial distribution tells us the probability of getting a specific number of successes with replacement (i.e., equivalent with shuffling your deck, revealing the top card, noting whether its a land or not, then shuffling again and repeating), the hypergeometric distribution takes into account that card draws are, in fact, not independent (i.e., telling us the probability of getting a specific number of successes without replacement, where cards arent reinserted into the deck after being counted as a success or not)
The only way to know exactly what quality of card you are buying is to buy a graded card
