I am starting a probability class and I am a bit confused looking at my textbook. An exercice is mentionning selecting cards randomly when another one says picking balls uniformly at random I have seen that a lot of posts are dealing about this but all of them have not made any sense to me unfortunately...
Could you explain me the difference between the two ? (if there is)
Complementary question :
If an exercice is saying: picking balls uniformly at random
How do I know if we take the four balls at the same time or the balls one by one ?
For the second question, you need to know if there is replacement, and when. Each ball replaced is different than all four replaced before the next operation, which is different than no replacement. Combinatorics with replacement is trickier, but Professor Woo on Youtube has excellent videos from 2013.