1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Probability: Is the manager telling the truth?

  1. Mar 5, 2014 #1
    1. The problem statement, all variables and given/known data

    The manager of a factory proclaims 99% of the products manufactured in his factory are unflawed. If we draw 50 products from 5000 products and find 2 of 50 are flawed, then how do we know the manage is telling the truth?

    2. Relevant equations

    Nothing special.

    3. The attempt at a solution


    [itex] \frac{{5000*0.99 \choose 48} {5000*0.01 \choose 2}}{ {5000 \choose 50}} \approx 0.0754 [/itex]

    Manager lied.

    Is this correct? Thank you in advance!
  2. jcsd
  3. Mar 5, 2014 #2


    User Avatar
    2017 Award

    Staff: Mentor

    You cannot conclude that the manager lied based on this result. You could have been unlucky with the 50 products. A probability of 7.5% is still reasonable and needs more tests before such a strong conclusion can be drawn.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted