I have a population of N=100 and I am taking a simple random sample without replacement of n=10. I am trying to figure out the inclusion probability of 1 unit (we can call it unit one) of the 100 possible units for the sample. My idea is that after selecting unit one, the other 9 units are represented by 99 choose 9, meaning there are 99 choose 9 random sample that include unit one. Then you take that and divide by the total number of possible sample, which is represented by 100 choose 10. So the answer is
99 choose 9/ 100 choose 10 = .1
Can someone verify that my answer is correct or incorrect?