A coin is tossed three times. Let X denote the number of times a tail follows a head. If and 2 denote the mean and variance of X, then the value of 64 ( + 2 ) is:
(4) 48
Count "HT" in the 8 outcomes: X=1 for HHT, HTH, HTT, THT; otherwise X=0.
P(X=1)=P(X=0)= 12, a Bernoulli variable with p= 12
= 12, 2=p(1-p)= 14
64( + 2)=64 34=48
Answer: (4)
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