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ECN224 Econometrics I – 2017
Questions and Answers
Question 1
a)
The integral of the probability density function of a random variable must equal one. Therefore, we
can integrate this over x and y as follows:
1 = 𝑥 + 𝑦 𝑑𝑦 𝑑𝑥
1
1 = [𝑥𝑦 + 𝑦 ] 𝑑𝑥
2
1
1 = 𝑥 + 𝑑𝑥
2
1 1
1 = [ 𝑥 + 𝑥]
2 2
1 1
1 = +
2 2
1 = 1
Therefore, this can be considered to be the joint probability density function of X and Y.
ECONOMICS HELP, visit LondonEconomicsTutors.co.uk.
Discounted prices compared to all other websites
ECN224 Econometrics I – 2017
Questions and Answers
Question 1
a)
The integral of the probability density function of a random variable must equal one. Therefore, we
can integrate this over x and y as follows:
1 = 𝑥 + 𝑦 𝑑𝑦 𝑑𝑥
1
1 = [𝑥𝑦 + 𝑦 ] 𝑑𝑥
2
1
1 = 𝑥 + 𝑑𝑥
2
1 1
1 = [ 𝑥 + 𝑥]
2 2
1 1
1 = +
2 2
1 = 1
Therefore, this can be considered to be the joint probability density function of X and Y.
