In: Statistics and Probability
Each of the 60 students in a class belongs to exactly one of the
three groups A,B, or C. The
membership numbers for the 3 groups are as follows:
A: 15 students
B: 20 students
C: 25 students
First, choose one of the 60 students at random and let X be the
size of that student’s group;.
Next, choose one of the 3 groups at random and let Y be its
size.
a. Write down the pmf for X and Y.
b. Compute ?(?) ??? ?(?).
c. Compute ???(?) ??? ???(?).