the answer is PMF(x,y) = Prob{X prefer nonsmokers and Y prefer smokers}
Support: 0<=X<=7, 0<=Y<=7, 0<=X+Y<=7.
PMF = Combinations(X of 7) * Combinations(Y of 7-X) * 0.78^X * 0.01^Y * 0.21^(7-X-Y)
(b)
The marginal PMF comes from summing the joint PMF over over Y. Alternatively, we can get it directly:
Support: 0<=X<=7
PMF(X) = Combinations(X of 7) * (0.78)^X * (0.22)^(7-X)
brainliest plzz worked really hard on this thxx god bless