Is probability subjective?

Originally posted by Evil Dead
no

oh come on -

FINE:

In which case please explain what the difference between sub-quantum length* and "quantum level" is.

* IE Planck Length

You're a bit of a jackass, aren't you?

Kids, quit it. Take it to PMs.

sorry boss.

isn't quantum level something to do with gravitational photons and something to do with atoms or something smaller then a atom?

Forgive me its been two years sine i did Quantum Mechanics as a elective at uni and i didn't do very well in it 😉

cry but it's better on forums 😛

Mr Zero.........I've spent my time in the classroom......so have you.......I'm not taking you're little test. I'm tired and need to go to bed.......I have to be up for work in 4 hours.

I came into this thread to discuss the topic.......not answer physics questions from you because you believe you're the only one who ever went to school and actually paid attention.

I'll be on tomorrow......we can discuss then. Reply to my PM and we can discuss as much as you want at my leisure.

ash007.........yes, quantum covers both atomic and sub-atomic........

now I'm out.

Originally posted by AMN Inc
I think it is. I don't believe there is any way the chance of something happening can be expressed as a number. In a world of infinite variables, how can events be reduced to something as primitive as numbers?

probability is a numerical value given to the chances of an event happening, based on the known data. So if i told you there were 2 out comes from flipping a coin, you could say the probably of heads to tails respectively is:

50:50

suppose i extended your knowledge.... the head's side weighs more, and is therefore more likely to land face down, you could say:

49:51

then i told you the point at which the person was flicking the coin, the angle, the strength, the air resistance... suppose i gave you every variable that would affect the flip of this coin? then we could say:

0:100

see, probability isn't exact. it's just a numberical value, based on what we know. if we knew everything, then every event could be predicted, and every event would have a value of 1 or 0.

since we don't know everything, we must use the given data to assess a value between 0 and 1 😄

You can't take _all_ factors into account, there are just too many. One obvious one would be the wind speed, which could possibly affect the toss.

Probability numbers are only useful in a non-existent "perfect world".

wind speed is a terrible example, because the speed could be 20mph, or 20.0001mph or 20.0002mph... you get the idea 😛

and what is a "perfect world", raz?

Actually wind speed is a good example of something unpredictable affecting the outcome.

The perfect non-existent theoretical world would be one where you can control, or at least know of, all the factors that would affect the outcome.

Originally posted by Raz
Probability numbers are only useful in a non-existent "perfect world".

Tell that to the people who get rich running loteries.

in a perfect world, probability wouldn't exist at all... since there's no "chance" of it happening, we know if it happens or not.

in a perfect world, probability = 1 or 0.... it is in an imperfect world where probability becomes useful for prediction.

Raz and others: It's true that you can only get 100% accurate results in perfect (mathematical) situations, but that doesn't mean that the results you get in the real world are useless. You can never know exactly how long something is, because no ruler is perfect, but the measurements you get are still useful; it's the same sort of thing with probability.

Which is true, and which is why probability is only good for guesstimates.

quite right gregory ✅

probability is the chance of something happening based on given variables...

but we must remember, the TRUE probability of an event is 1 or 0, but we can't give those numbers until AFTER the event has happened, or until we know EVERY variable

Then its not probability, but eventuality.

well if we get every variable prior to the event, and decide if it happens or not, it's probability

well, it's certainty

since its not probable it will happen.... it's certain