1. The problem statement, all variables and given/known data We have an urn with 5 red and 18 blues balls and we pick 4 balls with replacement. We denote the number of red balls in the sample by Y. What is the probability that Y >=3? (Use Binomial Distribution) 2. Relevant equations 3. The attempt at a solution Okay, so we were asked to use the Binomial Distribution here. The whole sample is denoted by N = 23. The number of trials is n = 4 since we have to choose 4 balls from 23. Since Y denotes the number of red balls in the sample and replacement is used, how do we find p? Is it the probability of having 3 red balls and one blues + the probability of 4 red balls? So, (5/23)^3 * (18/23) + (5/23)^4? What is k? Is it in our case 3 and 4? I will post the other hypergeometric problem when I solve this. I am not good at statistics in any way so I would appreciate the help.