Chapter 2: Problem 2
Let \(X\) represent the difference between the number of heads and the number of tails obtained when a coin is tossed \(n\) times. What are the possible values of \(X\) ?
Chapter 2: Problem 2
Let \(X\) represent the difference between the number of heads and the number of tails obtained when a coin is tossed \(n\) times. What are the possible values of \(X\) ?
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Get started for freeIf \(X\) is a nonnegative random variable, and \(g\) is a differential function with \(g(0)=0\), then $$ E[g(X)]=\int_{0}^{\infty} P(X>t) g^{\prime}(t) d t $$ Prove the preceding when \(X\) is a continuous random variable.
Prove that \(E\left[X^{2}\right] \geq(E[X])^{2}\). When do we have equality?
Suppose that the joint probability mass function of \(X\) and \(Y\) is $$ P(X=i, Y=j)=\left(\begin{array}{l} j \\ i \end{array}\right) e^{-2 \lambda} \lambda^{i} / j !, \quad 0 \leq i \leq j $$ (a) Find the probability mass function of \(Y\). (b) Find the probability mass function of \(X\). (c) Find the probability mass function of \(Y-X\).
Suppose a die is rolled twice. What are the possible values that the following random variables can take on? (a) The maximum value to appear in the two rolls. (b) The minimum value to appear in the two rolls. (c) The sum of the two rolls. (d) The value of the first roll minus the value of the second roll.
The density of \(X\) is given by $$ f(x)=\left\\{\begin{array}{ll} 10 / x^{2}, & \text { for } x>10 \\ 0, & \text { for } x \leq 10 \end{array}\right. $$ What is the distribution of \(X ?\) Find \(P[X>20\\}\).
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