Introductory Statistics 9th Edition

Let us denote Y = students that suffer from math anxiety, N = students do not suffer from math anxiety. Possible outcome : {YY, YN, NY, NN} a. Both students suffer from math anxiety={YY} = $\frac{1}{4}$ b. Exactly one student suffers from math anxiety={YN, NY} =$\frac{2}{4}$ c. The first student does not suffer from math anxiety and second suffers from math anxiety={NY} =$\frac{1}{4}$ d. None of the students suffer from math anxiety={NN} =$\frac{1}{4}$