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bertusgeert

YOUR probability of Death

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One of my profs is trying to prove something to me. He sent me this:

28 died out of 110,000 jumps in 1988 yielding a rate of 25/100,000 dead (about the same as driving in a car). http://www.afn.org/skydive/sta/stats.html



You can tell yourself whatever you want, but more than 1 in 1000 skydivers die (tandems which are statistically safer account for lots of the jumps).

30,000 USPA members, it's effectively impossible to be an active skydiver without being a USPA member, and there are about 30 annual deaths not including aircraft fatalities.

Of course that assumes that you have an average chance of owning a Cypres, average chance of flying a small canopy, average currency, etc.

1 in 1000 drivers didn't die in my high school in spite of us having a way above average chance of being young and stupid doing things like breaking 100 MPH on the way home from school in 1978 Trans-Ams.

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I know this is a bit old, but I see a big problem with the coin analogy.

The problem is that a coin has fairly equal chances at coming to rest on either side, H or T. This is not comparable to the risk factor in skydiving.

If you want to use a coin in an analogy, you have to use the third possibility of how a coin can come to rest - on edge.

If you tossed a coin on a flat surface, it is not impossible for a coin to come to rest on edge. This is comparable to the risk factor in skydiving.

Further, to expand the analogy, a thicker coin increases the possibility of it coming to rest on edge, so that can be compared to more dangerous skydiving activities.

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The Ol' Freefall Philosopher sez...

"Skydiving does not inevitably lead to death but, it is possible. Therefore, try to make as many jumps as you can before the event happens."
Look for the shiny things of God revealed by the Holy Spirit. They only last for an instant but it is a Holy Instant. Let your soul absorb them.

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(PS, your math is wrong JT, its approx. 1 death every 0.0003 jumps)

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Very true, don't know why I moved it 3 spots instead of 5?


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You CAN say that as a whole, there is 25% chance that someone will die every 1000 jump in the country. But on the individual, no, you cant.



I agree, but the post is title YOUR prob of death which means the individual



The quality of your mathematics suggests something about your beliefs about statistics.
...

The only sure way to survive a canopy collision is not to have one.

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I
Now let's consider the exchange between Bertusgeert ("Go do 10,000 jumps, and by the statistics, you will be lucky to still be alive") and The111 ("The silliest thing I've heard all day"). The estimated probability of death from attempting 10,000 skydives would be 8.7% (= 10,000/115,000) or about 1/12.



Your numbers are approximately correct ONLY because the probability of death on any one jump is so small, HOWEVER your method of calculation is incorrect - you don't just add up the probabilities. What you need to do for N jumps is to raise the probability of living (1 - prob. of dying) on a single jump to the power N. That gives the probability of surviving N jumps. Then subtract that from 1, and you get the probability of dying in N jumps**.

Which gives the prob. of dying in 10,000 jumps to be 8.3% assuming the single jump value quoted is correct.

** you have to do it that way because you can survive more than one jump, but you can't die on more than one jump.
...

The only sure way to survive a canopy collision is not to have one.

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Yes, I stand corrected on the calculation. Always glad to learn something new (or be reminded of something I should have remembered).

Of course, the point that cumulative probability of death rises with the number of jumps remains valid. I feel silly even bringing that up, but it was disputed when this thread originally started a couple of years ago.

Doug

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It is a fact that by far the majority of drivers claim that they are an "above average" driver - which is impossible.



A common misconception. The majority of a group CAN be better (or worse) than the average. A majority can NOT be better or worse than the MEDIAN.

Think about this in simple terms... If 9 people have 110 wigets each, and 1 person has only 10, then the average number of wigets is 100 per person. The majority of (actually, 9 out of 10, in this case) have more wigets than average.


On to the OP.... the math is completely correct. If your odds of dying are 28:110,000, then the odds of dying calculated for 1,000 and 10,000 jumps are correct.

However, the original data is wrong - shit in, shit out. The real data is, as has been posted, about 1:100,000 (btw, NOT safer than driving). However, calculating THOSE numbers, you get a 1% chance of dying in 1,000 jumps, and a 9.5% chance of dying in 10,000 jumps.

Also, as has been noted, this does not take into consideration the individual. There are quite a few risk factors you can take out, and decrease your chances of dying. Pulling low, swooping, not wearing an AAD - if you take out all of those fatalities (and don't do any of those things yourself), you dramatically increase your odds of survival.

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its like saying there is a death pool and for every jump you make you put a percentage of yout next jump into that pool.



Not at all.

If you do 10,000 jumps, you are more likely to die than if you do 1 jump. Fair enough?

Now, you are absolutely correct in saying that each jump is independent of the last one (save for currency and such, but we're not considering that). IE, by doing 9,999 jumps and surviving, you have not increased your odds of dying on that last jump. In our simplified world of probability (where skill and currency don't matter) you have the same probability of dying on the last jump as on the first, or on any other one in the middle. Each jump has the same probability of death.

All the total numbers are saying is that in doing a total of 10,000 jumps, you have a probability of X (a little under 10%, depending on the numbers you use) of dying on any ONE of those jumps.

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In my lifetime, I have literally dodged 'potential' death 5 times but I still have a 100% chance of dying. Makes one ponder.:|



Not if you believe the bible. Moses didn't die (wasn't him? Someone in the bible at least....) he just ascended into heaven. So if 1 in say 20 billion people haven't died, they just ascended, you have about a 1 in 20 billion chance of never dying :P

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I didn't know that about Moses. I thought is was Jesus who ascended into heaven but after he died and rose from the dead. Makes me ponder even more.

1 in 20 billion you say. There's better odds in Vegas.;)




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Chris






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I know this is a bit old, but I see a big problem with the coin analogy.

The problem is that a coin has fairly equal chances at coming to rest on either side, H or T. This is not comparable to the risk factor in skydiving.

If you want to use a coin in an analogy, you have to use the third possibility of how a coin can come to rest - on edge.

If you tossed a coin on a flat surface, it is not impossible for a coin to come to rest on edge. This is comparable to the risk factor in skydiving.

Further, to expand the analogy, a thicker coin increases the possibility of it coming to rest on edge, so that can be compared to more dangerous skydiving activities.



TRUTH IS, I died three times since my last post in this thread...AND I had coins in my pockets every time. I only carry paper money now.
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TRUTH IS, I died three times since my last post in this thread...AND I had coins in my pockets every time. I only carry paper money now.



Since money has been dropping in value lately, could we deduce from your statement that so is the value of your life?



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Chris






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I didn't know that about Moses. I thought is was Jesus who ascended into heaven but after he died and rose from the dead. Makes me ponder even more.

1 in 20 billion you say. There's better odds in Vegas.;)



I got un-lazy and looked it up. I was wrong, Moses did not ascend into Heaven. Elijah, Enoch, Paul, and John all did, according to some random website. I remember hearing that someone did, and I was thinking it was Moses off the top of my head.

So your odds are 4 times higher!

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If you want to use a coin in an analogy, you have to use the third possibility of how a coin can come to rest - on edge.

If you tossed a coin on a flat surface, it is not impossible for a coin to come to rest on edge. This is comparable to the risk factor in skydiving.

I've tossed a lot of coins and never seen one land on it's edge. I have seen a lot of people die skydiving. I don't think your analogy works.

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Hi John,
The point that I was trying to make was that a coin has a possibility of landing on edge that is greater than zero.

Also, the aspect ratio of the coin, diameter vs. thickness would make a difference. So if you had some hypothetical coin that was 1/4" thick x 3/4" in diameter, the chance would be a lot higher than a nickel.

With great number of variables that are involved in the chance of death in skydiving, you could also say that a coin landing on edge also has a great number of variables.

But for the sake of a simple analogy, most people can understand the coin on edge concept.

To really figure the chances of a fatality, I think it should be figured with chaos mathematics that one may use to try and predict weather or the stock market.

Even then then answer would be non-definitive and ambiguous.:S So why go through all that math? Just toss that thick coin.:D

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on any given jump,
fuck up and the probability approaches 100%, in an asymptotic curve ( I hear you saying bullshit ... and your right ... I barely remember what 'asymptotic' is .... but the rest is true....)

so ... just NEVER fuck up..... probability of death - almost zero (it can never be 0 because of Heisenberg's Uncertainty Principle).

so go be perfect.... like me B|B|B|

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