Probability Again

What was the answer for that questions .5 yes and .5 no and joint prob was .33. It should be independent, right?

It shouldn’t be independent, if independent P(AB)=p(A).P(B), so joint prob. is .25 I don’t remember the exact question…

Joint prob was 1 to 3 or .25, but I marked independent for that too. T/G

0.5 + 0.5 - 0.33 = 0.67? p(A) + p(B) - P(AB) = p(A or B) that was it asking right?

In they were independent, they would have to satisfy the following condition: p(A or B) = p(A) x p(B) - p(A and B), where p(A and B) is p(A) x p(B) Since 0.5x0.5 is not equal to 0.33, these event are not independent. The increase in probability of A and B happening is due to A and B being somewhat related.

so they are “related events” right?

1 to 3 IS NOT .333 it is .25 .5*.5=.25 Therefore the events are independent. answer was .25 and independent.

what test was test number was that on ?


The test said the odds of the event occurring together is “1 to 3” (if I recall correctly), which is .25, making the events independent. If they said 1 IN 3, then the odds of the event occurring would be .333 and would they be related. “in” vs “to” does anyone recall for sure? T/G

LongOnCfa is correct.

1010 or 2020 or ???..

95% sure it was 1 to 3…i remember thinking “this is gonna trick a lot of people”


It was. 100%.

i’m with LongOnCFA.

+1 for me. I owe you one LongonCFA

and -1 for me… but, I still cannot recall seeing 1 to 3. And, to make things worse, I had plenty of time to read everything carefully.

-1 for me too… I did not interpret 1 to 3 correctly.

LongOnCFA Wrote: ------------------------------------------------------- > 1 to 3 > > IS NOT .333 it is .25 > > .5*.5=.25 > > Therefore the events are independent. > > answer was .25 and independent. that’s how I reasoned it out as well. Thanks, LongOnCFA. Got scared there for a sec, I already found a bunch of mistakes, didnt want this to be another one. Dubs, it was on 1010. odd # page, second Q from the bottom