benny 0 #76 December 23, 2003 QuoteVery funny and very cynical. And very false. Man, I like you, at least you compliment me before ripping me! I know, I know, stats have value, hell, I'm an econ major, that's about all we do anymore. I was just pointing out that, in the case of no other outside factors, say, a random number generator, the odds of getting one number are simply 1:x possible numbers. I'd say physics could actually give a little better view of the parachute situation, and the coin toss, as both are affected by the laws of physics. I don't really hold a coin toss as being random. I mean, there are ways you can influence the outcome of a coin toss in just the way you flip it. Ok ok, thanks. Me off soapbox too. Obviously I don't believe what I said in that previous post or I wouldn't be hurling myself out of a plane this weekend. But hey, statistically it's safer than putting me behind the wheel. Never go to a DZ strip show. Quote Share this post Link to post Share on other sites
rehmwa 2 #77 December 23, 2003 I gotta go. Have to buy one more present for my little girl. I'm buying the first round if we ever meet. ... Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants Quote Share this post Link to post Share on other sites
sdctlc 0 #78 December 23, 2003 Here is a quick thought. You have a 50/50 chance to filp a heads or tails on a coin flip. If you hit 5 heads in a row what is the stastical chance that you will hit a tails on flip #6, 50/50! The chance of something happening is not an additive effect. i.e. The more you do something with a specific outcome then the more likely an increase in the chance of the negative or reversed outcome happening. It is not this way. Each separate event, like a coin flip, is at the actual or theoretical stated stastical likelyhood. Scott C."He who Hesitates Shall Inherit the Earth!" Quote Share this post Link to post Share on other sites
newsstand 0 #79 December 23, 2003 QuoteHere is a quick thought. You have a 50/50 chance to filp a heads or tails on a coin flip. If you hit 5 heads in a row what is the stastical chance that you will hit a tails on flip #6, 50/50! The chance of something happening is not an additive effect. i.e. The more you do something with a specific outcome then the more likely an increase in the chance of the negative or reversed outcome happening. It is not this way. Each separate event, like a coin flip, is at the actual or theoretical stated stastical likelyhood. As long as each coin flip is looked at independently that's right but if you look at them as a series it changes. At least I think that is what this is all about. Law of Large Numbers - http://stat-www.berkeley.edu/users/stark/Java/lln.htm "Truth is tough. It will not break, like a bubble, at a touch; nay, you may kick it about all day like a football, and it will be round and full at evening." -- Oliver Wendell Holmes Quote Share this post Link to post Share on other sites
billvon 2,395 #80 December 23, 2003 >If you inspecct your equipment before packing, pack properly and > deploy stable, there is no reason for you to have a mal . . . Nevertheless, malfunctions do happen on parachutes that are properly maintained, packed and deployed. You can reduce but not eliminate the odds of a mal through careful maintenance and packing. Quote Share this post Link to post Share on other sites
Liemberg 0 #81 December 23, 2003 Quoteyou can't in any way put a number on that. Although my favorite statistician calculates every chance to be fifty / fifty (it either happens or it doesn't), you can. If your chance for a double mal is 1 in 25000 (0,004%), than on any given jump your chance of no double mal is 99,996%. Your chance of 2 jumps in a row without a double mal would be 99,99200016% (which is a little less - your chance indeed is diminishing.) I'm to lazy to calculate this any further, but there will be a point where a series of N jumps without a double mal is highly improbable. For the sake of the argument we could say that after 12500 jumps, there is a turning point where the chance of making such a series or a larger one without a double mal is less likely than a double mal somewhere in the series (12500 is NOT correct BTW, intuitively I would guess it to be somewhere near 17000 - the 'break even' or turning point of MY favorite statistician) However, what does this mean? This means that if you start out and make your first jump today, it is a bad investment to buy 25000 non-refundable jump tickets. If everybody does that it will only make the DZO rich - it is unlikely that you all survive that long. However, when you started out 25 years ago and until today managed to make 24999 jumps, against all odds without killing yourself with a double mal, on jump number 25000 your chance of a double mal is again 0,004% Should you stop jumping at 25000 since statistically, you are dead? No, in fact it is unlikely but not impossible to make a series of well over 25000 jumps without a double mal, even if there is a double mal expected to happen every 25000 jumps. Soooo: This parachuting stuff appears to be a whole lot more hazardous for newbies, doesn't it? "Whoever in discussion adduces authority uses not intellect but memory." - Leonardo da Vinci A thousand words... Quote Share this post Link to post Share on other sites
Push 0 #82 December 23, 2003 Ok, since so many people seem to still have trouble with this fallacy, I'll try putting the explanation in different words. You have correctly calculated (24999/25000) ^ 25000 to be the probability that I will have a dmal in my next 25000 jumps. (The binomial distribution is irrelevant because you can only have one dmal before the sampling ends.) Now I go and make a jump. Assume I survive. The probability of me having a dmal in my next 25000 jumps remains as you calculated. The probability of me having a dmal by jump number 25000 is now (24999/25000) ^ 24999. If I go and make another jump, the power becomes 24998, et cetera. Now, the probability of me surviving my next jump is 24999/25000. When I make this jump, the probability of me surviving a second jump remains 24999/25000. However, the probability of someone else being me is now (24999/25000) ^ 2. So the probability of someone with 24999 jumps to survive the next is still 24999/25000, but the probability of picking a random skydiver and having them survive to the same jump numbers is (24999/25000) ^ 25000. I hope it's clearer now. -- Toggle Whippin' Yahoo Skydiving is easy. All you have to do is relax while plummetting at 120 mph from 10,000' with nothing but some nylon and webbing to save you. Quote Share this post Link to post Share on other sites
skydivegirl 0 #83 December 23, 2003 I always knew I was a math nerd but the fact that I'm still actively following this thread has finally made it official... Pink Mafia Sis #26 Quote Share this post Link to post Share on other sites
Push 0 #84 December 23, 2003 Join the dark side! -- Toggle Whippin' Yahoo Skydiving is easy. All you have to do is relax while plummetting at 120 mph from 10,000' with nothing but some nylon and webbing to save you. Quote Share this post Link to post Share on other sites
whatever 0 #85 December 23, 2003 dude check the excel spreadsheet I attached to my first post in this thread, it's got all those values you mentioned calculated... soon to be gone Quote Share this post Link to post Share on other sites
whatever 0 #86 December 24, 2003 thanks dude that's what I was trying to get across.... You just say it much clearer and simpler! soon to be gone Quote Share this post Link to post Share on other sites
benny 0 #87 December 24, 2003 QuoteI always knew I was a math nerd but the fact that I'm still actively following this thread has finally made it official... I find it comforting to know that if this thread is any indicator, I might actually fit in the world of skydiving. Who woulda thunk it that there would be so many math nerds jumping out of planes. I guess maybe that we are logical enough to realize that even though it's scary as shit, it's still statistically safer than driving! Never go to a DZ strip show. Quote Share this post Link to post Share on other sites
benny 0 #88 December 24, 2003 Quote I gotta go. Have to buy one more present for my little girl. I'm buying the first round if we ever meet. I'd say the odds are, I'll buy the second. Never go to a DZ strip show. Quote Share this post Link to post Share on other sites
Liemberg 0 #89 December 24, 2003 Quoteeven though it's scary as shit, it's still statistically safer than driving! No, it is not. (Common misconception among skydivers though, so there you DO fit in...) "Whoever in discussion adduces authority uses not intellect but memory." - Leonardo da Vinci A thousand words... Quote Share this post Link to post Share on other sites
fool 0 #90 December 24, 2003 Quote realize that even though it's scary as shit, it's still statistically safer than driving I think you'd better duck... hehehe S.E.X. party #1 "Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "f*#k, what a ride". Quote Share this post Link to post Share on other sites
benny 0 #91 December 24, 2003 QuoteQuoteeven though it's scary as shit, it's still statistically safer than driving! No, it is not. (Common misconception among skydivers though, so there you DO fit in...) hmm, well, it was only a preliminary search, but the data in 1991 show that with skydiving there was 1 fatality for every 65513 jumps, and 6.1 motor vehicle fatalities for every 50000 people (see http://www.afn.org/skydive/sta/stats.html and http://www.hwysafety.org/safety%5Ffacts/fatality_facts/general.htm). Hmm, methinks the stats prove me right. Never go to a DZ strip show. Quote Share this post Link to post Share on other sites
fool 0 #92 December 24, 2003 I don't think you can compare jumps to people... you could do jumps to drives, or people to people, but not mixing them like that. S.E.X. party #1 "Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "f*#k, what a ride". Quote Share this post Link to post Share on other sites
Maxim 0 #93 December 24, 2003 ***hmm, well, it was only a preliminary search, but the data in 1991 show that with skydiving there was 1 fatality for every 65513 jumps, and 6.1 motor vehicle fatalities for every 50000 people *** But you are comparing jumps and people here.. to make this true you would have to compare 65513 jumps to 65513 car trips... lets say all the people in that made 100 jumps on average that year, 65513 / 100 = only 655.13 people VS 50,000 people Life is Great. Even Greater what we do with it. Quote Share this post Link to post Share on other sites
benny 0 #94 December 24, 2003 Quote***hmm, well, it was only a preliminary search, but the data in 1991 show that with skydiving there was 1 fatality for every 65513 jumps, and 6.1 motor vehicle fatalities for every 50000 people *** But you are comparing jumps and people here.. to make this true you would have to compare 65513 jumps to 65513 car trips... lets say all the people in that made 100 jumps on average that year, 65513 / 100 = only 655.13 people VS 50,000 people Well I'd say the likelihood is that those people made many more "drives" during the year than 100. I drive at least twice a day. I'd say that hold true for about every American at least... making a total of... 730 drives per person per year (I think this is way conservative)... so, the numbers still seem to be in my favor in jumping out of an airplane vs driving a car. Never go to a DZ strip show. Quote Share this post Link to post Share on other sites
skypuppy 1 #95 December 24, 2003 QuoteQuoteWhen they go for the world record 25,000 way there is a high probablity that one person will have a dmal.Maybe, maybe not, but I'd say the probability of about 25000 canopy collisions is pretty high. Well, if they got it and then someone DID have a dmal, the record wouldn't count, because the rules state that everyone has to live for x number of hours afterwards before the record is official... But that's another story.If some old guy can do it then obviously it can't be very extreme. Otherwise he'd already be dead. Bruce McConkey 'I thought we were gonna die, and I couldn't think of anyone Quote Share this post Link to post Share on other sites
skypuppy 1 #96 December 24, 2003 Quote>If you inspecct your equipment before packing, pack properly and > deploy stable, there is no reason for you to have a mal . . . Nevertheless, malfunctions do happen on parachutes that are properly maintained, packed and deployed. You can reduce but not eliminate the odds of a mal through careful maintenance and packing. I still stand by the statement in my original post... Maybe years ago there was always a chance, but now it is very small if not zero...If some old guy can do it then obviously it can't be very extreme. Otherwise he'd already be dead. Bruce McConkey 'I thought we were gonna die, and I couldn't think of anyone Quote Share this post Link to post Share on other sites
Maximus1 0 #97 December 24, 2003 QuoteBy these estimates, the p(double) is 1 in 1,500,000 - which means its not a risk I'm loosing sleep over. Perhaps we should institute an Instant-Win reserve ride program a la: http://www.theonion.com/onion3013/airbag.html - Maximus It's not that I'm afraid to die, I just don't want to be there when it happens. Quote Share this post Link to post Share on other sites
Maximus1 0 #98 December 24, 2003 Quote730 drives per person per year That means 50,000 people would make 36.5M drives and have 1 fatality per 6M drives. That means driving a car is 91.5 times safer than jumping out of a plane. Hmmm, perhaps, statistically, that means that driving a car out of a plane is safer than jumping out of one... - Maximus It's not that I'm afraid to die, I just don't want to be there when it happens. Quote Share this post Link to post Share on other sites
Liemberg 0 #99 December 24, 2003 QuoteHmm, methinks the stats prove me right. Quoteyou could do jumps to drives, or people to people, but not mixing them like that. People who do this for a living compare fatalities per participants IIRC... Often, they are employed by insurance companies. (That should ring a bell, me thinks...)For instance: There are only a proportion of people who skydive that also do basejump. If you pool the fatalities (skydiving and base jumping fatalities added up) you'll find that the proportion of basejumping fatalities in that sum is larger than can be expected from the proportion of basejumping skydivers in the other pool; if both pastimes were just as dangerous / safe, you would find the same proportions in both pools you compare. Voila - you just proved what you knew all along: basejumping is more dangerous than skydiving. The same can be done for traffic participants who don't and traffic participants who do skydive. There is no way you'll get to the conclusion that skydiving is less dangerous than participating in traffic. (or driving if you will - but usually it is hard to discern the person driving the car from the occupants and the bystanders in the figures you find) Since this is the way actuarians calculate this stuff all the time and insurance companies manage to make ends meet, this must be correct, don't you think? "Whoever in discussion adduces authority uses not intellect but memory." - Leonardo da Vinci A thousand words... Quote Share this post Link to post Share on other sites
benny 0 #100 December 24, 2003 oh my god, i had nightmares last night about how i was gonna get reemed on this one. as soon as my head hit the pillow I knew that my math was just completely wrong! Oh well, that's the problem with drinking and doing math problems... or driving. Question, what do you guys think of (maybe just slightly) inebriated tandem passengers. I think the DZ could face liability issues if something happened. Legally, a non-sober person can't sign the waiver and all. Never go to a DZ strip show. Quote Share this post Link to post Share on other sites
