4Q. The joint probability mass function of discrete random variables ๐ X and ๐ Y is given by: ๐ [ ๐ = ๐ฅ , ๐ = ๐ฆ ] = { ๐ ( 4 ๐ฅ + ๐ฆ ) , ๐ฅ = 1 , 2 , 3 ย andย ๐ฆ = 1 , 2 , 3 0 , otherwise P[X=x,Y=y]={ k(4x+y), 0, โ x=1,2,3ย andย y=1,2,3 otherwise โ Find the value of ๐ k. Then, calculate ๐ ( ๐ = 2 ย andย ๐ = 3 ) P(X=2ย andย Y=3).
Question
4Q. The joint probability mass function of discrete random variables ๐ X and ๐ Y is given by:
๐ [ ๐
๐ฅ , ๐
๐ฆ ]
{ ๐ ( 4 ๐ฅ + ๐ฆ ) , ๐ฅ
1 , 2 , 3 ย andย ๐ฆ
1 , 2 , 3 0 , otherwise P[X=x,Y=y]={ k(4x+y), 0, โ
x=1,2,3ย andย y=1,2,3 otherwise โ
Find the value of ๐ k. Then, calculate ๐ ( ๐
2 ย andย ๐
3 ) P(X=2ย andย Y=3).
Solution
To find the value of k, we need to know that the sum of all probabilities in a probability mass function should be equal to 1.
Given that x and y can take values 1, 2, 3, we can write the total probability as:
Summation (x=1 to 3) Summation (y=1 to 3) P[X=x, Y=y] = 1
Substituting the given P[X=x, Y=y] = k(4x + y) into the equation, we get:
Summation (x=1 to 3) Summation (y=1 to 3) k(4x + y) = 1
Calculating the double summation, we get:
k[4(1+2+3) + (1+2+3)]*3 = 1 k[24 + 6]3 = 1 k90 = 1
So, k = 1/90.
Now, to calculate P(X=2 and Y=3), we substitute x=2 and y=3 into the equation P[X=x, Y=y] = k(4x + y):
P[X=2, Y=3] = k(4*2 + 3) = (1/90)*11 = 11/90.
Similar Questions
The joint distribution of ๐X and ๐Y is given byย ย ย ย ย ย ย ย ย ย ย ย ย ย ย ๐๐๐(๐ฅ,๐ฆ)=916ร4๐ฅ+๐ฆ,f XYโ (x,y)= 16ร4 x+y 9โ ,where ๐๐,๐๐โ{0,1,2,โฆ}.T Xโ ,T Yโ โ{0,1,2,โฆ}.1 pointFind the probability mass function of ๐+๐X+Y.๐916โ 4๐k 16โ 4 k 9โ (๐+1)916โ 4๐(k+1) 16โ 4 k 9โ (๐+1)916โ 4๐+1(k+1) 16โ 4 k+1 9โ ๐916โ 4๐+1k 16โ 4 k+1 9โ
For the Joint PMF as shown, find each of following quantities:๐๐ ๐ฅ , ๐๐ ๐ฆ , ๐๐|๐ ๐ฅ ๐ฆ , ๐๐|๐ ๐ฆ ๐ฅ , ๐ธ[๐|๐ = 3]Also find whether ๐ and ๐ are independent or not.[The graph shows ๐๐,๐(๐ฅ, ๐ฆ)/12]
The random variables X and Y have the joint PMF: px,y(x, y)=c*(x+y)^(2) if x belongs to {1,2,4} and y belongs to {1,3} and otherwise px,y(x,y) =0. Find the value of c. Find P(Y<X) and P(Y=X).
(30 points) Suppose Company 1's stock return ๐๐ is a random variable and takes three possiblevalues: {-0.1, 0.1, 0.2}. And Company 2's stock return ๐๐ is a random variable and takes twopossible values: {-0.3, 0.4}. The joint probability distribution ๐๐(๐๐, ๐๐) is given as follows:๐๐(โ0.1, โ0.3) = 0.1, ๐๐(0.1, โ0.3) = 0.2, ๐๐(0.2, โ0.3) = 0.2,๐๐(โ0.1,0.4) = 0.2, ๐๐(0.1,0.4) = 0.2, ๐๐(0.2,0.4) = 0.1.Please calculate the following:(a) Marginal distributions: ๐๐๐๐(๐ฅ๐ฅ) and ๐๐๐๐(๐ฆ๐ฆ). (4 points)(b) Mean: ๐ธ๐ธ(๐๐) and ๐ธ๐ธ(๐๐). (4 points)(c) Variance: ๐๐๐๐๐๐(๐๐) and ๐๐๐๐๐๐(๐๐). (4 points)(d) Covariance: ๐ถ๐ถ๐ถ๐ถ๐ถ๐ถ(๐๐, ๐๐). (2 points)(e) Conditional expectations: ๐ธ๐ธ(๐๐|๐๐ = โ0.3) and ๐ธ๐ธ(๐๐|๐๐ = 0.4). (8 points)(f) Conditional variances: ๐๐๐๐๐๐(๐๐|๐๐ = โ0.3) and ๐๐๐๐๐๐(๐๐|๐๐ = 0.4). (8 points)
Let X and Y be two random variables with joint probability mass function:P(X=i,Y=j) = (i+j)/36, for i,j=1,2,3,4What is the marginal probability mass function of X?Review LaterP(X=i) = 5(i+1)/36, for i=1,2,3,4P(X=i) = (5+i)/36, for i=1,2,3,4P(X=i) = 5/12, for i=1,2,3,4P(X=i) = (5i+1)/36, for i=1,2,3,4
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.