A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Pulsified333

  • one year ago

nvolving sets A and B. Suppose for this problem that Pr[A|B]=1/2, Pr[A]=1/5, and Pr[B′]=7/10. (1) What is Pr[B|A]? (2) What is Pr[B|A′]?

  • This Question is Closed
  1. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    hello again!

  2. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    hi :)

  3. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    you want \[P(A\cap B)\]right, so you can compute the ratio you need for both

  4. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1442891498761:dw|

  5. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\frac{P(A\cap B)}{P(B)}=P(A|B)\] you have two out of the three numbers you need to find \(P(A\cap B)\)

  6. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    we have A and P[A|B]

  7. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    you got \(P(B)\) and \(P(A|B)\) so you can solve for \(P(A\cap B)\)

  8. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    We have the complement of B

  9. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    but B = 3/10 Right?

  10. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah \[P(B)=\frac{3}{10}\]

  11. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    'cause you be sippin syrup that's why!

  12. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so its (3/10)*(1/2)

  13. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    hmm no

  14. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    oh yes!

  15. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    which is 4/5

  16. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    now that is wrong

  17. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ??

  18. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[\frac{1}{2}\times \frac{3}{10}=\frac{3}{20}\]

  19. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    my bad, im tired

  20. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    oh the multiplication is wrong, yeah

  21. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so Pr(B|A)= 3/4

  22. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @satellite73 how would you do (2)

  23. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    well i know A' is 4/5

  24. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[P(B|A')=\frac{P(A'\cap B)}{P(A')}\]

  25. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    but how do you Find P(A′∩B)

  26. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1442892611104:dw|

  27. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[P(B)=P(A\cap B)\]

  28. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    B= 3/10 and P(A∩B)=3/20

  29. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    now what?

  30. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @satellite73 is the answer (3/10)/(4/5)= 3/8

  31. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    dang i made a typo sorry, i meant to write \[P(B)-P(A\cap B)\]

  32. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    which equals 6/20

  33. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    that is your numerator \[P(A'\cap B)\]

  34. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    okay which is (3/10)/(4/5)?

  35. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    looks good to me

  36. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    but the answer 3/8 is wrong

  37. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    it is hard for me to keep scrolling up \[P(A')=\frac{4}{5}\] right?

  38. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

  39. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what is \(P(A\cap B)\)?

  40. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    3/20

  41. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    and what is \(P(B)\)

  42. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    3/10

  43. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so \[\frac{3}{10}-\frac{3}{20}=\frac{3}{20}\]

  44. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i messed up

  45. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so its (3/20)/(4/5)

  46. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    answer would be \[\frac{\frac{3}{20}}{\frac{4}{5}}\]

  47. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    3/16

  48. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    its right :D

  49. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yay

  50. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I wish i could give two medals but i Cant

  51. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    thanks i got plenty bought my bike with my first 1000

  52. Pulsified333
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    nice

  53. xapproachesinfinity
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    hmm that was the answer for one?

  54. xapproachesinfinity
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    P(B/A)

  55. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    lol no one is ancient history

  56. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    that was \[P(B|A')\]

  57. xapproachesinfinity
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    hehehe ah ok

  58. xapproachesinfinity
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Good computation :)

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

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.