Probability Theory : Probability Theory

Study concepts, example questions & explanations for Probability Theory

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Example Questions

Example Question #11 : Probability Theory

Let , and  be the lifespans (in hours) of two electronic devices, and their joint probability mass function is given below.


Determine the value of

Possible Answers:

Correct answer:

Explanation:

In order to find the value of , we need to take find the double integral of the function

Let's find what the bounds are for both , and

We look at the p.d.f to see that the bounds for  are, , and for ,

Now let's set up the double integral


Before we evaluate it, we need to remember to set the double integral equal to one, since we are essentially solving for the c.d.f.



Now evaluate the double integral


To evaluate this, we need to use the limit definition





Now we simply solve for

Example Question #12 : Probability Theory

Let , and  be the lifespans (in hours) of two electronic devices, and their joint probability mass function is given below.



Determine the value of .

Possible Answers:

Correct answer:

Explanation:

In order to find the value of , we need to take find the double integral of the function

Let's find what the bounds are for both , and

We look at the p.d.f to see that the bounds for  are, , and for ,

Now let's set up the double integral


Before we evaluate it, we need to remember to set the double integral equal to one, since we are essentially solving for the c.d.f.




Now evaluate the double integral


To evaluate this, we need to use the limit definition







Now we simply solve for

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