anonymous
  • anonymous
HELP WITH PROBABILITY! Question posted below :)
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
katieb
  • katieb
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
An art critic is surveying a gallery to find a piece that he would like to buy. The piece however has been copied by numerous people throughout the years such that 20% of the paintings in circulation are fake. the critic correctly identifies a fake as being fake 90% of the time; but only correctly identifies a real piece as being real half the time. The critic finds the painting and believes is is a fake. What is the probability that the painting is real? 40% 50% 69% 80%
anonymous
  • anonymous
Hi ganeshie8, I've drawn a tree diagram of probabilities, but am having some trouble making sense of the question...
ganeshie8
  • ganeshie8
80% of available pieces are real and 20% are fake : |dw:1437554345284:dw|

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
Yep :)
anonymous
  • anonymous
nice font btw
ganeshie8
  • ganeshie8
The probability for critic identifying "fake piece" as "fake" is 90% The probability for critic identifying "real piece" as "real" is 50% |dw:1437554570150:dw|
anonymous
  • anonymous
Yep, thats what I did too
ganeshie8
  • ganeshie8
fill in the probabilities on other braches |dw:1437554742335:dw|
anonymous
  • anonymous
Yep :)
ganeshie8
  • ganeshie8
we're given that the critic identifies the piece as fake, so highlight those branches : |dw:1437554822270:dw|
anonymous
  • anonymous
Okay, yes
ganeshie8
  • ganeshie8
p("real" | "c-fake") = P("real" and "c-fake") / P("c-fake")
ganeshie8
  • ganeshie8
= 0.8*0.5 / (0.8*0.5 + 0.2*0.9)
anonymous
  • anonymous
why do you divide those two?
ganeshie8
  • ganeshie8
because we know that the critic identified the piece as fake, the sample space reduces to only those two branches that end with "c-fake"
anonymous
  • anonymous
okay so out of all the times that he says its fake, we are looking at the times its actually real
ganeshie8
  • ganeshie8
Exactly!
anonymous
  • anonymous
woo hoo
anonymous
  • anonymous
Thanks so much for your help @ganeshie8 !!!!!!
ganeshie8
  • ganeshie8
np you could work this using bayee's theorem formula but i feel tree diagrams are a great way to visualize/work these problems involving conditional probability
anonymous
  • anonymous
whats bayee's theorem? If its quick to explain that would be great, otherwise ill wikipedia it!
ganeshie8
  • ganeshie8
check this https://www.khanacademy.org/computing/computer-science/cryptography/random-algorithms-probability/v/bayes-theorem-visualized

Looking for something else?

Not the answer you are looking for? Search for more explanations.