# Thread: Calculate conditional entropy

1. ## Calculate conditional entropy

Hello,

I have this information:

P(a, 1) = 0,4
P(a, 2) = 0,1
P(a, 3) = 0,05
P(a, 4) = 0,1

P(b, 1) = 0,05
P(b, 2) = 0,1
P(b, 3) = 0,3
P(b, 4) = 0,1

We have X1(x, y) = x and X2(x, y) = y so P(X2 = 1) = P({(a, 1); (b, 1)})

How can I Calculate H(X), H(Y) and H(Y|X)?

2. ## Re: Calculate conditional entropy

What does your book say to do? Where are you getting confused? How can we help clarify if you do not tell us what part you do not understand.

3. ## Re: Calculate conditional entropy

I missed the course so I'm not so sure. I think I have to use this:

Im not sure how I can use this with my numbers.
what would be the next step?

An Example would be helpful it doesn't have to be my example.
Ok, so what is $X$ and what is $Y$?