I'm your typical engineering student that's done only mechanics modules before and while now at uni, this is my first experience with statistics.
I've been trying to get better but not hard enough so I'm making this thread to keep a public record of my progress.
I'll also be asking question (not for full solutions this time ) but I'll post a question and may ask for a numerical answer to check my work to I'll post photos to ask if they're correct
And don't be shy other people, you can ask your statistics inquiries here as well, we can all learn together
My issues 1) Not entirely sure how to get the intersection part in the formula 2) I don't understand partitioning events with its compliment.
You're getting confused on what is conditioned on what. So let D be the event that the test detects corrosion and let CP be the event "corrosion present". Then you are given P(D | CP) = 0.7 and that P(D | ~CP) = 0.2 and P(CP) = 0.1.
You are asked to work out P(CP | D). Can you do that via Bayes' theorem? That is
You're getting confused on what is conditioned on what. So let D be the event that the test detects corrosion and let CP be the event "corrosion present". Then you are given P(D | CP) = 0.7 and that P(D | ~CP) = 0.2 and P(CP) = 0.1.
You are asked to work out P(CP | D). Can you do that via Bayes' theorem? That is
P(CP∣D)=P(D∣CP)P(CP)+P(D∣∼CP)P(∼CP)P(D∣CP)P(CP)
What does the sum of the denominator symbolize? Like I only know Bayes theorem to be P(Aj∣B)=i=1∑nP(Ai).P(B∣Ai)P(Aj).P(B∣Aj)
What does the sum of the denominator symbolize? Like I only know Bayes theorem to be P(Aj∣B)=i=1∑nP(Ai).P(B∣Ai)P(Aj).P(B∣Aj)
The sum in the denominator I have given is a special case of the one you have there. You have A1,A2,⋯An as a partition of the the probability space Ω; I have CP and not CP partitioning Ω.
The sum in the denominator I have given is a special case of the one you have there. You have A1,A2,⋯An as a partition of the the probability space Ω; I have CP and not CP partitioning Ω.
Oh ok, I think I understand but in part b I think I need to find P(CP|~D) ? I'm not sure how to operate with ~D since they didn't give D separately?
What if you post too much surely you'd get annoyed
That would defeat the purpose of the forum, everybody is welcome to post as many question as they'd like. I've helped a fair few people on here, and amongst those who post repeated questions, I can never once say that I felt annoyed by them as long as they were courteous.
That would defeat the purpose of the forum, everybody is welcome to post as many question as they'd like. I've helped a fair few people on here, and amongst those who post repeated questions, I can never once say that I felt annoyed by them as long as they were courteous.
Sometimes I'm just too dumb to understand and it might frustrate others.
Give it a try next time you get stuck, you'll be pleasantly surprised.
Chemistry is a slight bit more confusing to understand/explain. I often just shake my head in class saying I understand when I don't when miss explains.
Will try to make use of the Chem forum and try not to spend all my time on the Chat section