Maryann is testing the effectiveness of a new acne medication. There are 100 people with acne in the study. Fifty-five patients received the acne medication, and 45 other patients did not receive treatment. Thirty of the patients who received the medication reported clearer skin at the end of the study. Twenty-two of the patients who did not receive medication reported clearer skin at the end of the study. What is the probability that a patient chosen at random from this study took the medication, given that they reported clearer skin?

Question

perl · Answer

you can solve this using probability

perl · Answer

hold up , let me write the equations needed

perl · Answer

Let S = success (acne is cured) , F = fail (acne is not cured)
let  M = takes medication.  M ' = does not take med

anonymous · Answer

wouldnt takes med and success be the first one? 30/55

perl · Answer

but you are told that they received medication, so it would be 
P ( S | M )

perl · Answer

P ( S | M ) = 30 / 55

anonymous · Answer

oh oops should be 25

anonymous · Answer

|dw:1410491700894:dw|