Suppose there are 130 patients. Each patient was administered one of 6 drugs as follows:

Drug A: 25 patients

Drug B: 31 patients

Drug C: 13 patients

Drug D: 17 patients

Drug E: 28 patients

Drug F: 16 patients

What is the probability that in a random sample of 4 patients, all 4 selected were administered drug A?

My answer is (25/130)^4

The answer in the back is 0.0823 but something tells me it is wrong.