Knowee
Questions
Features
Study Tools

Linearity of expectation II) Let X, Y be random variables and a, b, and c be constants. Use propertiesof integration/summation to show that:E(aX + bY + c) = aE[X] + bE[Y ] + c

Question

Linearity of expectation II) Let X, Y be random variables and a, b, and c be constants. Use propertiesof integration/summation to show that:E(aX + bY + c) = aE[X] + bE[Y ] + c

🧐 Not the exact question you are looking for?Go ask a question

Solution 1

Sure, here is the step-by-step proof:

  1. The expectation of a random variable is defined as the sum (for discrete variables) or the integral (for continuous variables) of the variable multiplied by its probability. So, E(aX + bY + c) is the sum or integral of (aX + bY + c) times its probability.

  2. By the properties of integration or summation, this can be broken down into three separate sums/integrals: a times the sum/integral of X times its probability, plus b times the sum/integral of Y times its probability, plus the sum/integral of c times its probability.

  3. The sum/integral of X times its probability is just the expectation of X, E[X], and similarly for Y. The sum/integral of c times its probability is just c, because the probability sums/integrates to 1.

  4. Therefore, E(aX + bY + c) = aE[X] + bE[Y] + c, which completes the proof.

This problem has been solved

Solution 2

Sure, here is the step-by-step solution:

  1. The expectation of a random variable is defined as the sum (for discrete variables) or the integral (for continuous variables) of the variable multiplied by its probability. So, E(aX + bY + c) is the sum or integral of (aX + bY + c) times its probability.

  2. By the properties of integration or summation, this can be broken down into three separate sums or integrals: a times the sum or integral of X times its probability, plus b times the sum or integral of Y times its probability, plus the sum or integral of c times its probability.

  3. The sum or integral of X times its probability is just the expectation of X, E[X], and similarly for Y. The sum or integral of c times its probability is just c, because the sum or integral of a constant times a probability is just the constant (since the sum or integral of the probabilities is 1).

  4. Therefore, E(aX + bY + c) = aE[X] + bE[Y] + c, as required.

This problem has been solved

Similar Questions

(Linearity of expectation I) Let X be a random variable, and a, b be constants. Use properties ofintegration/summation to show that:E(aX + b) = aE[X + b]

E[aX + bY + c]

Let X and Y be two discrete random variables with the given pmf pX (xi),i = 1, 2, . . . , n, and pY (yj ), j = 1, 2, . . . , m. Verify for following properties using thedefinition E[X] = ∑ni=1 xipX (xi).• (linearity) E[aX + bY + c] = aE[X] + bE[Y ] + c.• (monotonicity) If X ≤ Y , E[X] ≤ E[Y ].

Let X and Y be two continuous random variables, Find E(X+Y)*E(X)+E(Y)E(X)-E(Y)E(X)E(Y)E(X)/E(Y)

This question refers to the random variables X and Y from Question 1. Use your calculatedvalues from that question while answering this question.(a) Let Z = Y − aX, where a is a constant to be specified. There is one value of a for whichX and Z are uncorrelated. Find this value of a. [3 marks](b) Let W = X − bY , where b is a constant to be specified. There is one value of b for whichY and W are uncorrelated. Find this value of b. [3 marks](c) Verify that ab = ρ2X,Y

1/1

Upgrade your grade with Knowee

Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.