A random process flips a fair coin four times determine the

Question

A random process flips a fair coin four times. Determine the pmf for each of the following random variables:

• X = number of heads before first tail (4 if no tails),
• Y = number of heads after first tail (0 if no tails),
• Z = absolute difference between number of heads and number of tails,
• W = product of number of heads and number of tails.