Question

If A and B are independent events, then P(A l B)=?

Answer 1

What do you mean by A l B? "Or"?

Answer 2

P(A and B) / P(B) = P(A)*P(B) / P(B) = P(A).

Answer 3

A | B means, "A, given B", or "the event that A occurs, given that B has occurred".

Answer 4

wait then shouldn't it be dependent because A only occurs when B has occurred?

Answer 5

Ah, yes, even trivially \(P(A)\) if they are independent.

Answer 6

sorry i'm so bad at probability :(

Answer 7

A does not occur only when B occurs...we are simply choosing to only consider the cases when B has occured.

Answer 8

can you give an example please?

Answer 9

The probability that you roll a six given that the coin you flip beforehand is heads. It's still one in six, since you omit the cases when you fip tails.

Answer 10

Let's say A is we roll a one on a die, and B is we flip a coin and get heads. So, we're asking what the probability is of rolling a one after we just flipped a heads. It's still 1/6, because the coin doesn't matter.

Answer 11

Wow, yakey, how did we come up with the EXACT same example??

Answer 12

Wow...interestingly similar examples hahaha.

Answer 13

Great minds, etc. :P

Answer 14

Hahaha agreed.

Answer 15

if i could give 2 medals :(

Answer 16

ty guys !

Answer 17

No prob. Does it all make sense now?

Answer 18

yep