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tucsonalex
Feb 20, 2004, 12:23 AM
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This thread has been quiet the past few days, but the recent backclipping thread is too good to ignore.
http://www.rockclimbing.com/forums/viewtopic.php?topic=52397&forum=23
Steakboy started it all with this statement
In reply to: We all hear about how not to backclip a draw bacause the rope might get unclipped. I'm just asking if anyone has ever had this happen to them. A few weeks ago, me and some friends did an experiment where we took lots of whippers on a backclipped draw on an overhanging route so the falls were clean. Out of over fifty whippers, we NEVER became unclipped. so what's so bad about backclipping?
But there's going to be a lot of gumby nominations coming out of that thread after all the dust clears.
*edited to remove undeserving nomination.
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jt512
Feb 20, 2004, 12:25 AM
Post #127 of 414
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In reply to: Namascar deserves mention for achievements in gumby math In reply to: That means, with 95% confidence, that the 'unclipping rate' can be in reality as high as 7.13%, or as low as 0%. Assuming the usual stuff....
Hmmm, I don't know. His math was actually correct.
-Jay
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tucsonalex
Feb 20, 2004, 12:27 AM
Post #128 of 414
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In reply to: Hmmm, I don't know. His math was actually correct. -Jay
Do you mind explaining it Jay? I just didn't see where he came up with those figues.
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dirtineye
Feb 20, 2004, 1:20 AM
Post #129 of 414
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The back clipping thread is great.
I think it puts all the others to shame.
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jt512
Feb 20, 2004, 1:54 AM
Post #130 of 414
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In reply to: In reply to: Hmmm, I don't know. His math was actually correct. -Jay Do you mind explaining it Jay? I just didn't see where he came up with those figues.
It's a binomial probability problem. The experiment consisted of 50 trials, each of which had two possible outcomes. Such trials are called Bernoulli trials, and the question was this: given 0 "successes" (ie, unclippings), in 50 Bernoulli trials, what is the true probability of a success? This can only be estimated, and one way to do that is to calculate the exact 95% confidence interval (CI) around the true probability. The 95% CI is the interval that has a 95% probability of straddling the true probability of unclipping. The lower limit of this interval is trivial to determine when the number of successes is 0. It must be possible for the true probability to be 0, since that was the outcome of the experiment, and probabilities cannot be less than 0, by definition. Therefore, when the number of successes is 0, the lower limit of the 95% CI is 0.
The upper limit is more difficult to calculate. Let:
n=the number of Bernoulli trials in the experiment
k=the number of successes in the experiment,
p=the true probability of success, and
b[k]=the probability of obtaining k successes in n trials, given p
Then, the probability of the outcome of the experiment being k or less, given n and p, is given by:
Sum(b[k]) = [n! / (n-k)!k!] * p^k * (1-p)^(n-k), where b[k] is summed over the interval [0,k]. The upper 95% confidence limit is the value of p for which Sum(b[k]) = 0.025 [ie, (1 - .95) / 2].
Since, in the present instance, k = 0, we luck out, since there is no summing to do. In this case, it is practicable to iteratively choose values for p that result in b[k] converging to 0.025. Of course, nobody does such calculations by hand, even in the "easy" case where k=0. Statistical software packages will calculate these values for you. When that guy posted the CI, I checked it by using SAS.
As Hillary would say...HTH
-Jay
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moabbeth
Feb 20, 2004, 2:44 AM
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This is hands down the most entertaining thread since the "Bored posters flaming other posters" thread last fall. That one will be hard to top but this one is starting to come close.
And Hillary and Andrew, you were BOTH key to making THAT thread as awesome as it was. THIS thread has been resurrected from mere laugh inducing to full blown reading entertainment thanks to the two of you.
*sniff*...I love you guys...I really mean it :wink: :P !!
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bnjohns
Feb 20, 2004, 4:15 AM
Post #132 of 414
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In reply to: In reply to: In reply to: Hmmm, I don't know. His math was actually correct. -Jay Do you mind explaining it Jay? I just didn't see where he came up with those figues. It's a binomial probability problem. ...
Jay's post rocked. There's not enough probability being discussed on this site. I prefer Stata myself however.
:D
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climbsomething
Feb 20, 2004, 7:08 AM
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In reply to: *sniff*...I love you guys...I really mean it :wink: :P !! |
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tucsonalex
Feb 20, 2004, 3:43 PM
Post #134 of 414
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Thanks, Jay. It's been a while since I've done any probability problems. As I recall, Bernoulli did a great job of putting me to sleep when I studied him.
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camhead
Feb 20, 2004, 3:46 PM
Post #136 of 414
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yup, that steakboy is TOTALLY gumbitarded.
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calamity_chk
Feb 20, 2004, 3:49 PM
Post #137 of 414
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In reply to: This is hands down the most entertaining thread since the "Bored posters flaming other posters" thread last fall. That one will be hard to top but this one is starting to come close. And Hillary and Andrew, you were BOTH key to making THAT thread as awesome as it was. THIS thread has been resurrected from mere laugh inducing to full blown reading entertainment thanks to the two of you.
*hurt*
*sniff*
*cry*
i remember throwing mud in that thread. though, with my posts gone, it probably looks like enigma is just yelling at herself - haha.
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nnichols
Feb 20, 2004, 7:07 PM
Post #139 of 414
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By the way, how many of you wear helmets and have you seen K2 or Into Thin Air??????
:roll:
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crazygirl
Feb 20, 2004, 8:03 PM
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how many of you wear helmets while watching K2 or Into Thin Air??????
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jbird
Feb 20, 2004, 8:12 PM
Post #141 of 414
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how many of you wear thin helmets and watch k2???
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climbersoze
Feb 20, 2004, 9:23 PM
Post #142 of 414
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I wore my helmet when I went to see Vertical Limit... does that count? Everyone at the theatre kept touching my rack. It was nice. :)
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the_pirate
Feb 20, 2004, 9:53 PM
Post #143 of 414
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I like to wear my helmet to Baskin Robbins. They give an extra scoop if they think you're retarded.
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crotch
Feb 20, 2004, 10:46 PM
Post #144 of 414
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Towards the end of "50 First Dates" there's a scene in the brain injury ward where a patient is wearing a Petzl helmet.
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climbsomething
Feb 20, 2004, 10:50 PM
Post #145 of 414
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In reply to: Towards the end of "50 First Dates" there's a scene in the brain injury ward where a patient is wearing a Petzl helmet.
mandidyouseethatsceneinverticallimit? lol lol yeahcamsjustfail, that'slikeincliffhanger, wherethechicksharnessbroke lol lol anddidyouseestallone'sboltgun?
That brain injury ward patient wasn't a real climber, man!!!!!!!11 I hate the way climbing is portrayed to MountainDewposers!!!!!!!!11
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andy_reagan
Feb 20, 2004, 11:43 PM
Post #146 of 414
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Alex, I nominate you. :wink:
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tucsonalex
Feb 20, 2004, 11:47 PM
Post #147 of 414
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In reply to: Alex, I nominate you. :wink:
You obviously haven't read the entire thread.
In reply to: As the founder of the GotY Awards and a member of the judging panel I am immune from being nominated for, or winning a GotY Award
Who's the gumby now? :D
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andy_reagan
Feb 20, 2004, 11:51 PM
Post #148 of 414
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In reply to: Who's the gumby now?
I thought I already clarified that for you. :roll:
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tucsonalex
Feb 20, 2004, 11:58 PM
Post #149 of 414
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In reply to: In reply to: Who's the gumby now? I thought I already clarified that for you. :roll:
Weak, just another variation on "I know you are but what am I?".
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andy_reagan
Feb 21, 2004, 12:00 AM
Post #150 of 414
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shall I continue to keep proving your gumbiness or are we finished here? :wink:
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