4. A monkey types on a 26-letter keyboard that has lowercase letters only. Each letter is chosen independently and uniformly at random from the alphabet. a. Suppose the monkey types n letters. Let X be an indicator random variable and X=1 if "proof" appears at index i (assuming i 4. A monkey types on a 26-letter keyboard that has lowercase letters only. Each letter is chosen independently and uniformly at random from the alphabet. a. Suppose the monkey types n letters. Let X be an indicator random variable and X=1 if "proof" appears at index i (assuming i