In a research study, one third of the volunteers received drug A, one third received drug B, and one third received a placebo. Out of all the
volunteers, 10% received drug A and got better, 8% received drug B and got better, and 12% received the placebo and got better. What is the conditional probability of a volunteer getting better if they were given drug B?

Question

In a research study, one third of the volunteers received drug A, one third received drug B, and one third received a placebo. Out of all the 
volunteers, 10% received drug A and got better, 8% received drug B and got better, and 12% received the placebo and got better. What is the conditional probability of a volunteer getting better if they were given drug B?

ganeshie8 · Answer

What is the conditional probability of a volunteer getting better if they were given drug B?

ganeshie8 · Answer

u know that,  they were given drug B

ganeshie8 · Answer

so forget about everything else,
oly focus on drug B volunteers

highschoolmom2010 · Answer

ok 1/3 volunteers were given drug B 8% got better

ganeshie8 · Answer

how much % volunteers who took drugB are getting better ?

ganeshie8 · Answer

I said, forget about everything.

ganeshie8 · Answer

1/3 is irrelevent here cuz, we already know that the volunteer was given drugB

ganeshie8 · Answer

so the probability for getting better, when u give drugB to a volunteer is simply 8%
or 0.08

ganeshie8 · Answer

this is called conditional probability, cuz we're conditioning over drugB.

ganeshie8 · Answer

having known that the volunteer was given drugB, the probability for getting better is 0.08

highschoolmom2010 · Answer

oh ok so .08

ganeshie8 · Answer

yes !

highschoolmom2010 · Answer

ok so what do i do now?

ganeshie8 · Answer

we're done.
the conditional probability is 0.08

highschoolmom2010 · Answer

my book says it is 24% any idea on what to do

ganeshie8 · Answer

no idea about textbook answer,
probability for getting better, given that drugB was given is 0.08

highschoolmom2010 · Answer

me either

ganeshie8 · Answer

wait a sec, the percentages given dont belong to just the drug groups

ganeshie8 · Answer

they belong to all volunteers :/

ganeshie8 · Answer

Out of all the 
volunteers, 10% received drug A and got better, 8% received drug B and got better, and 12% received the placebo and got better.

ganeshie8 · Answer

that means, out of all the volunteers there were "8% ppl who received drugB and got better"

ganeshie8 · Answer

right ?

highschoolmom2010 · Answer

yes

ganeshie8 · Answer

that means in the drugB group, there will be 24% since we have divided the overall population into 3 equal groups. 24% in drugB group manifests as 8% in overall group

earlier i was wrong sorry i misread the question :(

highschoolmom2010 · Answer

oh i see now that makes sense :) ty @ganeshie8