# question about the conservation of probability

926

Some people say that probability is always the same, so if you flip a coin 10 times the chance is 50% always.

But there are some people that think different, they think that each new flip, the chance decrease, so

1- 50%
2- 50-50%= 25%
3- 25-50%= 12%
4- 12-50%= 6%
5- 6-50%= 3%

That topic is 100% related to trading, that i'm sure, so what do you guys think about that?

i tried to flip a coin 5 times, and never got the same sequence, tails or head, so i can assume 3% is a right number, 6 times giving the same side would be next to impossible.

If i assume its 50%, imagine 20 times, i get only tails, that would not be crazy? Believing that the probability remains the same is really hard to be plausible in reality.

So then i question, do you think probability is the same each try, or it decreases each new one?

480
cxan_96

The probability of each independent toss of a coin remains at 50%.

However, if you want to calculate the probability of a certain sequence of coin tosses, lets say HEADS - TAILS - TAILS, it can be calculated as you described by multiplying 50% * 50% * 50%, because the tosses are independent of each other.

If you want to calculate the probability of getting a certain number of HEADS in a sequence, take a look at the binomial distribution.

Moderator
8178

Ah another brain fart.

Of course it's always 50%.

The coin can not remember the last flip.

Only in Blackjack, the next card is influenced by the cards that already dealt because they are removed from the deck.

You can not say that if the first 100 flips was heads, there is more chance that the next flip will be tails.

It can only happen if the tosser has mastered the skill of flipping coins, so that he is able to manipulate the result !

But then, It's the tosser, not the coin...

By this i mean experience in tossing a coin, similarly to traders having mastered the skill of trading.

Watch this: The Dominator - Master of the dice where they show that it is possible to master THE SKILL of rolling dice...

Watch this: Breaking Vegas - Bringing down the house where they show that it is possible to master THE SKILL of blackjack.

All of those people had to put in the hard work and many hours, day's year's to become a master.

They didn't talk, they practiced until it became a habit.

When are you going to master the skill of trading ?

hahaha,

926

yes you're right, probabilities don't decrease, it was stupid

to make sure i manually flipped a coin 100 times, and the results where:

e e e e e c c c c c e e e c c e c c e c e e e e e c e c c e c c e c c c c e e e c c e e e e c c
e e e c c c e c c e c e c c e c c c c e c c e c e e e c c c e c e e c e e c c c e c c e e c e e e e e

theres was several consecutive tails, and head, that would likely not fit the idea that probabilities decrease, so you're right i guess

Moderator
8178

mrluck1:

yes you're right, probabilities don't decrease, it was stupid

to make sure i manually flipped a coin 100 times, and the results where:

e e e e e c c c c c e e e c c e c c e c e e e e e c e c c e c c e c c c c e e e c c e e e e c c
e e e c c c e c c e c e c c e c c c c e c c e c e e e c c c e c e e c e e c c c e c c e e c e e e e e

Flip it 256 times and you have a new Bitcoin address.