00:01
Okay, so here's a setup for this question here.
00:04
We let a, b, and c denote the event that a given company, that a given appliance came from company a, b, and c, respectively.
00:15
And d be the probability, or the event, sorry, that a given appliance is defective.
00:23
Okay, so the probability of a, we know the company a produces, the probability of an appliance coming from company a is 0 .15, company b, 0 .4, company c, 0 .45.
00:39
Furthermore, probability that company a's appliance is defective is 0 .01, and we have similar probabilities for company b and c being defective.
00:52
Okay, so here we are interested in calculating the probability of a given d, which by, which, which we can then use base theorem to write like this.
01:03
So probability of d given a, probability of a.
01:08
Okay, and then the denominator, you just write probability of d given a times probability of a plus probability d given b time probability of c, plus probability of b given c, probability of c.
01:23
Okay, so now we just plug in numbers...