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Posted on 5/6/19 at 9:09 pm to USMEagles
Yea its not like the Monty hall problem. In the OP scenario the “contestant” does not have a choice to change their selection.
1 sock is removed from the pool of 22. You need to pick its match out of the 21 remaining socks. 1/21 is the probability you pick the matching sock in the next pull.
1 sock is removed from the pool of 22. You need to pick its match out of the 21 remaining socks. 1/21 is the probability you pick the matching sock in the next pull.
Posted on 5/6/19 at 9:09 pm to RandySavage
quote:
Sally has 11 pairs of socks in her drawer. Each pair is a different color and design, but they are not together as pairs; they are just in her drawer scattered about. With her left hand, Sally reaches in and picks one sock. a. While holding that one sock in her left hand, Sally reaches into the drawer and picks another sock. What is the probability of her getting a sock that will match the sock in her left hand? Just want to make sure I'm doing this right?
quote:
it's actually a doctoral level stats class
Posted on 5/6/19 at 9:11 pm to genro
quote:They do.
Why don't the odds add up then?
quote:Ok.
There can only be 11 different first socks. Because they are interchangeable pairs.
quote:Sock 1 (already drawn) has a 1/21 chance of getting its mate on the second draw. Right. You should have stopped there.
So Sock 1 has a 1/21 chance of getting its mate
Sock 2 has a 1/21 chance
Etc
To Sock 11
quote:I have no idea how you got to 11/21, but the answer you're looking for is 1/21 is right and 20/21 are wrong, and that adds up to 21/21.
That's only 11/21. What are the other 10 possibilities? Answer that.
Posted on 5/6/19 at 9:11 pm to RandySavage
Edit. Used wrong value for first sock pick (1/22 should have been 2/22)
1. 2/22 * 1/22 = 2/ 462 = 1/231 (odds of drawing a sock from full drawer, odds of drawing that sock's mate after one sock has been picked)
2. 1/231*11 = 1/21. (sum the probabilities for all 11 pairs; probability is the same because there are equal numbers, 2, of each type of sock)
My Tutor Probability Sock Drawer Style
1. 2/22 * 1/22 = 2/ 462 = 1/231 (odds of drawing a sock from full drawer, odds of drawing that sock's mate after one sock has been picked)
2. 1/231*11 = 1/21. (sum the probabilities for all 11 pairs; probability is the same because there are equal numbers, 2, of each type of sock)
My Tutor Probability Sock Drawer Style
This post was edited on 5/6/19 at 9:46 pm
Posted on 5/6/19 at 9:12 pm to castorinho
Maybe that's phrased wrong, it's a stats class in a doctoral leadership program. The degree itself is obviously not in math. Just trying to learn the basics to conduct and present research I suppose.
Posted on 5/6/19 at 9:12 pm to Korkstand
Korkstand's math matches mine, but he did a better job of showing his work.
I wondered about Monty Hall right off the bat, but I'm still thinking it's 1 in 21.
I wondered about Monty Hall right off the bat, but I'm still thinking it's 1 in 21.
Posted on 5/6/19 at 9:13 pm to genro
quote:
That's only 11/21. What are the other 10 possibilities? Answer that.
The second sock that matches each of the ten pairs? Come on now. You can pick two completely different socks in terms of the fibers that make them up, but you are only counting them as one.
Posted on 5/6/19 at 9:14 pm to vidtiger23
If Johnny had 20 complete living room outfits, disregard color scheme, how many different sets of five complete outfits could be arranged?
Posted on 5/6/19 at 9:15 pm to RandySavage
who cares man, we made the champions league yesterday 
Posted on 5/6/19 at 9:16 pm to Korkstand
quote:
It's not. The answer is 1/21.
There are some people in this thread who really struggles with math...
Posted on 5/6/19 at 9:17 pm to RandySavage
When the door opens to reveal the goat behind it the odds change
Posted on 5/6/19 at 9:18 pm to OweO
quote:I think, and hope, that most of them are just confusing themselves assuming that the problem must be more difficult than it is. And genro might be trolling, I haven't decided yet.
There are some people in this thread who really struggles with math...
Posted on 5/6/19 at 9:19 pm to RandySavage
16+15+14+13+12+11+10+9+8+7+6+5+4+3+2+1=136
ETA: probably more than that
ETA: probably more than that
This post was edited on 5/6/19 at 9:22 pm
Posted on 5/6/19 at 9:22 pm to RandySavage
But not all socks are created equally, 21/100 chance of getting a matching sock
Posted on 5/6/19 at 9:25 pm to East Coast Band
Yea the formulas I'm seeing on the video give me factorials but then the number is over a million which doesn't seem right at all.
Posted on 5/6/19 at 9:28 pm to fgggg50
I believe 1/42 is the correct answer.
11(1/22 x 1/21)
11(1/22 x 1/21)
This post was edited on 5/6/19 at 9:30 pm
Posted on 5/6/19 at 9:29 pm to RandySavage
I added each number. I bet you need to multiply them.
If it's 6 sets, there would be 6 combinations. If it's 7 sets, there would be 42 combinations, I think.
So, if it's 20, it's gonna be a shite ton.
Something like 6*7*8*9*10*11*12*13*14*15*16*17*18*19*20
If it's 6 sets, there would be 6 combinations. If it's 7 sets, there would be 42 combinations, I think.
So, if it's 20, it's gonna be a shite ton.
Something like 6*7*8*9*10*11*12*13*14*15*16*17*18*19*20
This post was edited on 5/6/19 at 9:30 pm
Posted on 5/6/19 at 9:31 pm to RandySavage
The sock picker was her mother!
Posted on 5/6/19 at 9:35 pm to anc
1/21 is correct. I erred when I said probability of first pick is 1/22. It would be 2/22 because there are 2 of each kind of sock in the mix.
That doubles everything, making the probability 2* 1/42 =2/42=1/21.
That doubles everything, making the probability 2* 1/42 =2/42=1/21.
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