Bernoulli distribution - Exercise set 1

This exercise set contains some solved exercises on the Bernoulli distribution. The theory needed to solve these exercises is introduced in the lecture entitled Bernoulli distribution.

Exercise 1.1

Let X and Y be two independent Bernoulli random variables with parameter p. Derive the probability mass function of their sum:[eq1]

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The probability mass function of X is:[eq2]The probability mass function of Y is:[eq3]The support of Z (the set of values Z can take) is: [eq4]The formula for the probability mass function of a sum of two independent variables is:[eq5]where $R_{Y}$ is the support of Y. When $z=0$, the formula gives:[eq6]When $z=1$, the formula gives:[eq7]When $z=2$, the formula gives:[eq8]Therefore, the probability mass function of Z is:[eq9]

Exercise 1.2

Let X be a Bernoulli random variable with parameter $p=1/2$. Find its tenth moment.

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The moment generating function of X is:[eq10]The tenth moment of X is equal to the tenth derivative of its moment generating function, evaluated at $t=0$:[eq11]But[eq12]so that:[eq13]

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