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(1) A population consists of 3 households, labeled 1,2, and 3. The number of per

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Question

(1) A population consists of 3 households, labeled 1,2, and 3. The number of persons livingin each household and their incomes are given in the following table:

 

Household

Number of inhabitants

Incomes

1

1

$10,000

2

2

$10,000 , $20,000

3

3

$10,000 , $20,000 , $30,000

 

A household is selected at random with all households equally likely. Then a person isselected from the household with all people equally likely. Let X denote the numberof the selected household, and let Y denote the income of the selected person.

 

(i) Write down the probability mass function (frequency function) for X. This is thefunction pX dened by pX(x) = P[X = x] for each possible x.

 

(ii) Write down the conditional probability mass function (frequency function) for Ygiven X. This is the function pY |X dened by pY |X(y|x) = P[Y = y|X = x] foreach possible x, y pair.

 

(iii) Write down the joint probability mass function (frequency function) for X, Y. Thisis the function pXY dened by pXY (x, y) = P[X = x, Y = y] for each possible x, ypair.

 

(iv) Find the probability mass function (frequency function) for Y.

 

(v) What is the conditional probability mass function (frequency function) for Xgiven Y ? Given that the income of the sampled person is $10,000, what is theprobability distribution of the house number?

 

(vi) Find the expected value of X and the expected value of Y.

 

(vii) Find the variance of X and the variance of Y.(viii) Find the covariance between X and Y.



Household





Number of inhabitants





Incomes





1





1





$10,000





2





2





$10,000 , $20,000





3





3





$10,000 , $20,000 , $30,000



Explanation / Answer

Here there are 3 varaibles: housenumber, number of persons, income.
You did not mention which variable is to be taken as X and which varaible as Y