A probability distribution for a random variable Y is given by P(Y=y)=cy, for y=1,2,4,5 and c is a constant. Find E(Y), the expected value of Y. Give your answer as a fraction in its simplest form.

Now we can find the expected value with this formula:

And replacing we got:

Step-by-step explanation:

For this case we know the following probability mass function given:

For this case we need to satisfy the following condition in order to have a probability distribution function:

And we have this:

Now we can find the expected value with this formula:

And replacing we got: