Conditional probability tree diagram example | Probability | AP Statistics | Khan Academy

Using a tree diagram to work out a conditional probability question. If someone fails a drug test, what is the probability that they actually are taking drugs?

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[aaronastolfi]

Sal got me through my engineering degree, thank you!

[bivshiyzek]

Fascinating! Thanks, Sal, I'm your biggest fun. I skipped a lot at school, and you're helping me to fill in the gaps. Greetings from Brazil.

[sasi]

I love this the best probability video I've ever played. Thanks

[ethanmartinez]

The way he explains math better than anyone else <3

[rafansyed]

Sal tryna explain that he didn't do drugs
You're not fooling anyone

[JimO]

Did he mix up false negative and positives, or am I just confused?

[obeytheMIGHTY]

shouldnt you multiply the 500 on drugs by the true positive rate not the true negative rate

[yassinovo]

if it is stated that 5% of the applicants are actually on drugs, shouldn't the test be irrelevant when selecting randomly?

[Hossam]

But aren't the 2% actually on drugs also since they tested positive? Since the 2% is a false positive rate, they got the result of not being on drugs incorrectly. So given the applicant tests positive, the probability they are actually on drugs are 100%. (I'm overthinking this maybe..)

[marianedaguno]

Is this a dependent or independent pls someone tell me