G Consider the experiment of a single roll of an honest die and a single toss of 3 fair coins. Let X be the value on the die and let Y be the number of heads obtained on the coins. Find the joint probability function of X and Y

The probability function of X and Y is

With k in {1,2,3,4,5,6}

Step-by-step explanation:

We can naturally assume that X and Y are independent. Because of that, P(X=a, Y=b) = P(X=a) * P(Y=b) for any a, b.

Note that, since the die is honest, then P(X=k) = 1/6 for any k in {1,2,3,4,5,6}. We can conclude as a consequence that P(X=k, Y=l) = P(Y=l)/6 for any k in {1,2,3,4,5,6}.

Y has a binomial distribution, with parameters n = 3, p = 1/2. Y has range {0,1,2,3}. Lets compute the probability mass function of Y:

Thus, we can conclude that the joint probability function is given by the following formula

For any k in {0,1,2,3,4,5,6}

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x