COMP 480/580 Probabilistic Algorithms and Data Structures Luay Nakhleh Tail Bounds Computer Science Rice University
What Is This About? ❖ How large can a random variable get? ❖ In other words, how far can a value that the random variable takes be from its mean?
mean
mean tails
mean how large? tails
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Recall ❖ A random variable is a function from the sample space of an experiment/process to the set of real numbers. ❖ A coin is tossed twice. Let X(t) be the random variable that equals the number of heads that appear when t is the outcome. Then X(t) takes on the following values: ❖ X(HH)=2 ❖ X(HT)=X(TH)=1 ❖ X(TT)=0
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