You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
How to calculate probability?
- Thread starter colerelm
- Start date
Can anyone help me figure out how to get started on this problem from my assignment? I'm not asking for the answers, rather I'd like to know what steps should be taken to solve the problem. Any help would be appreciated, thanks.
View attachment 2374
I'll give you a hint for (a). You want P(~Y). It may help to ask yourself, what is the probability that I will choose ~Y from the two Z groups. So you must find the marginal distribution for ~Y for both Z and ~Z as it occurs in both groups. For Z, P(~Y) = 0.36 (do you see how I got that?), yet P(Z) = 0.60 (again, do you see how I got that?). Thus, P(~Y) for the Z group is (0.36)*(0.60) = 0.216.
Now try and find P(~Y) for the ~Z group. Then what do you think you do with these two amounts?
I'll give you a hint for (a). You want P(~Y). It may help to ask yourself, what is the probability that I will choose ~Y from the two Z groups. So you must find the marginal distribution for ~Y for both Z and ~Z as it occurs in both groups. For Z, P(~Y) = 0.36 (do you see how I got that?), yet P(Z) = 0.60 (again, do you see how I got that?). Thus, P(~Y) for the Z group is (0.36)*(0.60) = 0.216.
Now try and find P(~Y) for the ~Z group. Then what do you think you do with these two amounts?
Alright, thanks. I was able to figure it out with that info but I guess I'm stuck on part B now. I have a formula written down in my notes but I'm not sure if it's correct, can anyone confirm it?
P(x|~y) = [P(x)P(~y|x)]/P(~y)]
I've solved for P(x) but how do I calculate P(~y|x)?
Thanks again