Your explanation is so wrong mathematically.
In your example, the odds that the first person is legitimate is 97,000/100,000 = 97%. The odds that the second player is legitimate is 96,999/99,999 = 96.99997%. The odds that the third person is legitimate is 96,998/99,998 = 96.99994%. So on and so forth for the first 21 distinct players.
To calculate the overall probability that all 21 players are not cheater/toxic, you need to multiple all the percentages together. When you do this, the final probability is 52.7% which approximates the binomial distribution of 0.97^21.
If you still do not believe me, you can check the math online as shown below.
If you do not believe me, please find a link to a binomial calculator.
Binomial Probability Calculator (stattrek.com)
Probability of success on a single trial Enter 0.97
Number of trials Enter 21
Number of successes (x) Enter 21This mathematical result that can be independently verified demonstrate that if 3% cheat, then after encountering 21 players, the odds are roughly half (47.3%) that at least one of those 21 players is a cheater.
If you still won’t believe the mathematical truth, here is someone else’s explanation.
The end result is the same.
Hypergeometric
If the population is 200000, and 6000 (3%) are cheaters. We grab a collection of 21 players, and look for 0 players who is cheating.
with(Statistics); X := RandomVariable(Hypergeometric(200000, 6000, 21)); evalf(Probability(X = 0));
Result: 52.7%.
Binomial
Ignoring max population, we are looking for 21 legitimate players out of 21 players.
with(Statistics); X := RandomVariable(Binomial(21, 0.97)); Probability(X = 21);
Result: 52.7%
I disagree with pretty much everything MicroRNA says, always, but whether you like it or not, that’s university statistics for you.