Knowee
Questions
Features
Study Tools

Let (๐‘‹, ๐‘Œ ) be a discrete bivariate random vector with joint p.m.f. given by๐‘“๐‘‹,๐‘Œ (๐‘ฅ, ๐‘ฆ) =(๐‘ ยท ๐‘ฅ๐‘ฆ if ๐‘ฅ โˆˆ {1, 2, 3}, ๐‘ฆ โˆˆ {1, 2, 3}0 otherwisewhere ๐‘ > 0 is an as-of-yet undetermined constant.(a) Find the value of ๐‘

Question

Let (๐‘‹, ๐‘Œ ) be a discrete bivariate random vector with joint p.m.f. given by๐‘“๐‘‹,๐‘Œ (๐‘ฅ, ๐‘ฆ) =(๐‘ ยท ๐‘ฅ๐‘ฆ if ๐‘ฅ โˆˆ {1, 2, 3}, ๐‘ฆ โˆˆ {1, 2, 3}0 otherwisewhere ๐‘ > 0 is an as-of-yet undetermined constant.(a) Find the value of ๐‘

๐Ÿง Not the exact question you are looking for?Go ask a question

Solution

To find the value of ๐‘, we need to use the properties of a probability mass function (p.m.f).

First, we know that the sum of all the probabilities in a p.m.f must equal 1. Therefore, we can set up the equation:

โˆ‘โˆ‘ ๐‘“๐‘‹,๐‘Œ (๐‘ฅ, ๐‘ฆ) = 1

Since ๐‘‹ and ๐‘Œ can take on values from {1, 2, 3}, we can substitute these values into the equation:

๐‘“๐‘‹,๐‘Œ (1, 1) + ๐‘“๐‘‹,๐‘Œ (1, 2) + ๐‘“๐‘‹,๐‘Œ (1, 3) + ๐‘“๐‘‹,๐‘Œ (2, 1) + ๐‘“๐‘‹,๐‘Œ (2, 2) + ๐‘“๐‘‹,๐‘Œ (2, 3) + ๐‘“๐‘‹,๐‘Œ (3, 1) + ๐‘“๐‘‹,๐‘Œ (3, 2) + ๐‘“๐‘‹,๐‘Œ (3, 3) = 1

Substituting the given p.m.f into the equation, we have:

๐‘ ยท 1 ยท 1 + ๐‘ ยท 1 ยท 2 + ๐‘ ยท 1 ยท 3 + ๐‘ ยท 2 ยท 1 + ๐‘ ยท 2 ยท 2 + ๐‘ ยท 2 ยท 3 + ๐‘ ยท 3 ยท 1 + ๐‘ ยท 3 ยท 2 + ๐‘ ยท 3 ยท 3 = 1

Simplifying the equation, we get:

๐‘(1 + 2 + 3 + 2 + 4 + 6 + 3 + 6 + 9) = 1

๐‘(36) = 1

Dividing both sides by 36, we find:

๐‘ = 1/36

Therefore, the value of ๐‘ is 1/36.

This problem has been solved

Similar Questions

b) Find ๐‘๐‘Œ (๐‘ฆ), the marginal p.m.f. of ๐‘Œ

Suppose that (๐‘‹, ๐‘Œ) follows a bivariate normal distribution ๐‘(๐œ‡1, ๐œ‡2, ๐œŽ12, ๐œŽ22, ๐œŒ) with๐œ‡1 = ๐œ‡2 = 0 , ๐œŽ12 = 1 , ๐œŽ22 = 2 , and ๐œŒ = 1/โˆš2. eet ๐‘ˆ = ๐‘Ž๐‘‹ + ๐‘๐‘Œ , ๐‘‰ = ๐‘๐‘‹ + ๐‘‘๐‘Œ , findthe four equations that constants ๐‘Ž, ๐‘, ๐‘, ๐‘‘ need to satisfy such that ๐‘ˆ and ๐‘‰ areindependent standard normal random variables (no need to solve the equations). (10 points

(30 points) Suppose Company 1's stock return ๐‘‹๐‘‹ is a random variable and takes three possiblevalues: {-0.1, 0.1, 0.2}. And Company 2's stock return ๐‘Œ๐‘Œ is a random variable and takes twopossible values: {-0.3, 0.4}. The joint probability distribution ๐‘“๐‘“(๐‘‹๐‘‹, ๐‘Œ๐‘Œ) is given as follows:๐‘“๐‘“(โˆ’0.1, โˆ’0.3) = 0.1, ๐‘“๐‘“(0.1, โˆ’0.3) = 0.2, ๐‘“๐‘“(0.2, โˆ’0.3) = 0.2,๐‘“๐‘“(โˆ’0.1,0.4) = 0.2, ๐‘“๐‘“(0.1,0.4) = 0.2, ๐‘“๐‘“(0.2,0.4) = 0.1.Please calculate the following:(a) Marginal distributions: ๐‘“๐‘“๐‘‹๐‘‹(๐‘ฅ๐‘ฅ) and ๐‘“๐‘“๐‘Œ๐‘Œ(๐‘ฆ๐‘ฆ). (4 points)(b) Mean: ๐ธ๐ธ(๐‘‹๐‘‹) and ๐ธ๐ธ(๐‘Œ๐‘Œ). (4 points)(c) Variance: ๐‘‰๐‘‰๐‘Ž๐‘Ž๐‘Ÿ๐‘Ÿ(๐‘‹๐‘‹) and ๐‘‰๐‘‰๐‘Ž๐‘Ž๐‘Ÿ๐‘Ÿ(๐‘Œ๐‘Œ). (4 points)(d) Covariance: ๐ถ๐ถ๐ถ๐ถ๐ถ๐ถ(๐‘‹๐‘‹, ๐‘Œ๐‘Œ). (2 points)(e) Conditional expectations: ๐ธ๐ธ(๐‘‹๐‘‹|๐‘Œ๐‘Œ = โˆ’0.3) and ๐ธ๐ธ(๐‘‹๐‘‹|๐‘Œ๐‘Œ = 0.4). (8 points)(f) Conditional variances: ๐‘‰๐‘‰๐‘Ž๐‘Ž๐‘Ÿ๐‘Ÿ(๐‘‹๐‘‹|๐‘Œ๐‘Œ = โˆ’0.3) and ๐‘‰๐‘‰๐‘Ž๐‘Ž๐‘Ÿ๐‘Ÿ(๐‘‹๐‘‹|๐‘Œ๐‘Œ = 0.4). (8 points)

eet the joint p.d.f. of X1 and X2 be:โ„Ž(๐‘ฅ1, ๐‘ฅ2) = {8๐‘ฅ1๐‘ฅ2 for 0 < ๐‘ฅ1 < ๐‘ฅ2 < 10 otherwisea) Find the joint p.d.f. of ๐‘Œ1 = ๐‘‹1๐‘‹2and ๐‘Œ2 = ๐‘‹2b) Are ๐‘Œ1 and ๐‘Œ2 independent? Why? (10 points

For the Joint PMF as shown, find each of following quantities:๐‘๐‘‹ ๐‘ฅ , ๐‘๐‘Œ ๐‘ฆ , ๐‘๐‘‹|๐‘Œ ๐‘ฅ ๐‘ฆ , ๐‘๐‘Œ|๐‘‹ ๐‘ฆ ๐‘ฅ , ๐ธ[๐‘‹|๐‘Œ = 3]Also find whether ๐‘‹ and ๐‘Œ are independent or not.[The graph shows ๐‘๐‘‹,๐‘Œ(๐‘ฅ, ๐‘ฆ)/12]

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.