00:01
So it's known that engineering students feel like they've done really well on a final exam 20 % of the time.
00:06
So well, we're going to do well 20 % which means we're going to put not well as 80%.
00:14
Now if they feel like they've done really well, they go to the pub afterwards 30 % of the time.
00:22
So we're going to go our pub will be 30 % and if they feel like they didn't do well, then they go to the pub 80 % of the time.
00:31
So that's going to be our pub.
00:33
After a final exam, suppose you walk into a pub, see one of the engineering classmates.
00:37
What's the probability that they did well on the final exam? well, let's figure out how many went to the pub.
00:44
20 % of the well students went to the pub 30 % of the time.
00:48
So we'll go .2 times .3 and then 80 % of the non well went to the pub 80 % of the time.
00:56
So we'll go .8 times .8.
00:59
This is going to be .64.
01:01
This will be .06...