Integration of random variables

In summary, The problem is asking to find the expected value of Y given X. The equation for E[Y|X] is given as the integral of y times the joint probability density function divided by the marginal density function of X. In this case, the marginal density function of X is (2x+3)/(5exp(x)). When solving the integral, the outcome should be a function of x.
  • #1
nikki92
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Homework Statement



f(x,y)= (4/5)(x+3y)exp(-x-2y) for x,y, >0

Find E[Y|X]

Homework Equations



E[Y|X] =integral y *f_xy (x,y)/ f_x (x) dy

The Attempt at a Solution



f_x (x) = integral [o,∞] [4/5](x+3y)exp(-x-2y) dx = (2x+3)/(5exp(x))

When taking the integral of y[(4/5)(x+3y)exp(-x-2y)] / [(2x+3)/(5exp(x)) ] dy dx for [0,∞] for y (x+3)/(2x+3) is that correct?
 
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  • #2
well, if it's conditional, and it's dependent on x, shouldn't your outcome be a function of x?
 
  • #3
Oh my bad, I just got mixed up with definitions. Thanks! <3
 

Related to Integration of random variables

1. What is the definition of the integration of random variables?

The integration of random variables is the process of calculating the area under the curve of a probability distribution function. It is used to determine the likelihood of a certain outcome or range of outcomes occurring within a given set of data.

2. How is the integration of random variables related to probability?

Integration of random variables is directly related to probability as it allows us to calculate the probability of a specific event or range of events occurring within a set of data. It is a fundamental concept in probability theory and is essential for understanding and analyzing random phenomena.

3. What is the difference between discrete and continuous random variables in terms of integration?

Discrete random variables have a finite number of possible outcomes and can be represented by a probability mass function. Integration for discrete random variables involves summing the probabilities of each outcome. Continuous random variables, on the other hand, have an infinite number of possible outcomes and are represented by a probability density function. Integration for continuous random variables involves calculating the area under the curve of the probability density function.

4. How is the integration of random variables used in real-world applications?

The integration of random variables has various applications in fields such as finance, engineering, and statistics. It is used to calculate probabilities in risk assessment, model and analyze complex systems, and make predictions based on historical data. It is also used in statistical inference to estimate unknown parameters and make decisions based on data.

5. What are some common techniques for integrating random variables?

Some common techniques for integrating random variables include the use of the cumulative distribution function, the moment-generating function, and the characteristic function. Other methods such as Monte Carlo simulation and numerical integration techniques can also be used for more complex integrals. The choice of technique depends on the specific distribution and the desired level of accuracy in the integration.

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