probability question

[Dr. Sacrebleu]

I am pretty certain it is. if you're multiplying a bunch of numbers, it doesn't matter what order they are in. the only reason he frames it that way (I agree it's slightly confusing) is to make note of the fact that the probability of selecting a red or black ball change slightly after each ball is drawn.

 

98% is the correct answer, that much I am sure of beyond a reasonable doubt.

 

SO Matt70 with his answer of 100% is actually the closest with his guess.

OUCH

 

I was going to guestimate 75%

[muck]

Here I have a couple of urns. The one on the left contains 70 red balls and 30 black. The one on the right contains 30 red and 70 black.

 

While you weren’t looking, I reached into one of these urns and randomly drew out a dozen balls. As you can see, 4 of them were red and 8 were black.

 

Here are three questions that I think you ought to be able to answer if you want to be in the business of assessing evidence:

 

1.If you had to guess, which urn would you guess I drew from?

2.What’s your estimate of the odds that you’re right?

3.Do you think you’re right beyond a reasonable doubt?

*********************************************

 

1) Right urn.

2) I think this will help with the answer.

3) Probably not as I would prefer to have some of the evidence Cliaz also suggested.

[muck]

FWIW, without reading Azz's post about how the math is calculated, I used the exact same procedure (scary) and was going to put 97.8871% as my answer. Again, FWIW.

[billay]

FWIW, without reading Azz's post about how the math is calculated, I used the exact same procedure (scary) and was going to put 97.8871% as my answer. Again, FWIW.

Is there a difference between the chances of being right about which jar was selected and the chances of pulling that particular combination out of that particular jar? I suppose the reason why the percentage is so high is that not only are you dealing with an increased likelihood from one jar, but also a reduced likelihood from the other.

[muck]

Is there a difference between the chances of being right about which jar was selected and the chances of pulling that particular combination out of that particular jar? I suppose the reason why the percentage is so high is that not only are you dealing with an increased likelihood from one jar, but also a reduced likelihood from the other.

 

It does not matter the order you use in determining the probabilities out of one jar, as long as you use the exact same order when determining the probabilities of the other jar ... and then compare the relative probabilities to come up with your ratio ... which is 97.8871% in any event.

[Dr. Sacrebleu]

FWIW, without reading Azz's post about how the math is calculated, I used the exact same procedure (scary) and was going to put 97.8871% as my answer. Again, FWIW.

 

Of course that answer would mean you failed the test

[Azazello1313]

thoughts on the "reasonable doubt" question here

[Clubfoothead]

 

I expect this answer from club ("it's 50/50, like a parachute")....but come on, fellas.

 

anyway, I'll post some more on this tonight or tomorrow...

 

Well the thing's either going to open or not.

 

I would have said left, 99% and depends on the charges.

[Jackass]

I am pretty certain it is. if you're multiplying a bunch of numbers, it doesn't matter what order they are in. the only reason he frames it that way (I agree it's slightly confusing) is to make note of the fact that the probability of selecting a red or black ball change slightly after each ball is drawn.

 

98% is the correct answer, that much I am sure of beyond a reasonable doubt.

 

After looking at this thread again, it began to bug me so i looked up the probability formula. You can calc the # of combinations using 100!/ 88!*12! and then do something similar with the red and black balls. Picking 8 red and 4 black out of 12 balls is about a 25% chance and picking 4 red and 8 black is .5%. So 98% is exactly right. It looks like your formula does indeed work.