Chapter 2: Problem 48
If \(X\) is uniformly distributed over \((0,1)\), calculate \(E\left[X^{2}\right]\).
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Chapter 2: Problem 48
If \(X\) is uniformly distributed over \((0,1)\), calculate \(E\left[X^{2}\right]\).
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If a fair coin is successively flipped, find the probability that a head first appears on the fifth trial.
Suppose a die is rolled twice. What are the possible values that the following random variables can take on? (i) The maximum value to appear in the two rolls. (ii) The minimum value to appear in the two rolls. (iii) The sum of the two rolls. (iv) The value of the first roll minus the value of the second roll.
Show that the sum of independent identically distributed exponential random variables has a gamma distribution.
Let \(\phi\left(t_{1}, \ldots, t_{n}\right)\) denote the joint moment generating function of \(X_{1}, \ldots, X_{n}\). (a) Explain how the moment generating function of \(X_{i}, \phi_{X_{i}}\left(t_{i}\right)\), can be obtained from \(\phi\left(t_{1}, \ldots, t_{n}\right)\). (b) Show that \(X_{1}, \ldots, X_{n}\) are independent if and only if $$ \phi\left(t_{1}, \ldots, t_{n}\right)=\phi_{x_{1}}\left(t_{1}\right) \cdots \phi_{X_{n}}\left(t_{n}\right) $$
An individual claims to have extrasensory perception (ESP). As a test, a fair coin is flipped ten times, and he is asked to predict in advance the outcome. Our individual gets seven out of ten correct. What is the probability he would have done at least this well if he had no ESP? (Explain why the relevant probability is \(P\\{X \geqslant 7\\}\) and not \(P\\{X=7\\} .)\)
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