Question

Help me find Q please!!
For mutually exclusive events R1, R2, and R3, we have P(R1)=0.05, P(R2)=0.4, P(R3)=0.55. Also P(Q|R1)=0.5, P(Q|R2)=0.7, and P(Q|R3)=0.4.

Find P(R2|Q).

Answer 1

P(R2/Q)=P(R2 and Q)/P(Q)
we have P(Q/R2)=P(R2 and Q)/P(R2)
hence P(R2 and Q)= 0.7P(R2)=0.7x0.4=0.28

Answer 2

we need P(Q) now!

Answer 3

isnt 1-P=Q?

Answer 4

P of what? p here means probability!
so probability of what event are you talking about

Answer 5

1-P(R2)?

Answer 6

I think there a formula that link P(A/B) with P(B/A) sort of thing
but i forget

Answer 7

that will be true if Q is complement of R2
but that's not true?

Answer 8

ahh idk im just guessing, i'm not too good at this :/

Answer 9

We need that formula to get this done!
and used the fact the those events are mutually exclusive!

Answer 10

use*

Answer 11

ill look for it!

Answer 12

@SolomonZelman probab hehe

Answer 13

@nincompoop