How do probabilities balance the odds?

In summary, the probability of black does not increase as more reds occur in a roulette game. This is because each roll is independent and the odds remain the same every time. The concept of the "law of averages" is a common misconception and the mathematical definition of probability is not directly related to the actual frequency of an event.
  • #1
DarkFalz
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Let's consider a simple roulette game, where one may either get red or black. Since the probabiblity P of an event A, P(A) is defined as the relative frequency at which the event occurs, if we get red , say 3 times in a row, it is very likely that the next random pick will be black.

My question is, does this mean that the probability of Black increases as more reds occur? consider a person that only joins the roulette game when several reds have occurred before he joins and bets on black, will he never have a high probability of winning?
 
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  • #2
DarkFalz said:
Let's consider a simple roulette game, where one may either get red or black. Since the probabiblity P of an event A, P(A) is defined as the relative frequency at which the event occurs, if we get red , say 3 times in a row, it is very likely that the next random pick will be black.

My question is, does this mean that the probability of Black increases as more reds occur? consider a person that only joins the roulette game when several reds have occurred before he joins and bets on black, will he never have a high probability of winning?

If you get 3 reds in a row, it makes no difference to the probability that the next roll is red or black. It's the same roulette table with the same odds every time.

Yours is a common misconception about the "law of averages". Imagine tossing a coin until you get, say, 4 heads in a row and then taking that coin and making a bet based on the false assumption that the next throw is likely to be tails. What if you toss the coin straight away or leave it a day? - or put it in a drawer for a year? - how would that coin remember that it had 4 heads in a row and ought to come up tails next time?
 
  • #3
DarkFalz said:
Since the probabiblity P of an event A, P(A) is defined as the relative frequency at which the event occurs

That is not the mathematical definition of probability. The probability of an event can't be directly related to actual frequency of the event except by statements that tell about the probability of an actual frequency.
 

1. How do probabilities and odds relate to each other?

Probabilities and odds are two different ways of expressing the likelihood of an event occurring. Probabilities represent the chances of an event happening as a fraction or decimal, while odds represent the ratio of the likelihood of an event occurring to the likelihood of it not occurring. In other words, odds are the ratio of the number of successful outcomes to the number of unsuccessful outcomes.

2. What is the difference between odds and probability?

The main difference between odds and probability is their representation. While probabilities are expressed as fractions or decimals, odds are typically written in the form of a ratio. Additionally, probabilities range from 0 to 1, while odds can range from 0 to infinity.

3. How can one calculate probabilities from odds?

To calculate probabilities from odds, use the following formula: P(event) = odds / (odds + 1). For example, if the odds of winning a game are 2:1, the probability of winning would be 2 / (2 + 1) = 0.667, or 66.7%.

4. How do probabilities and odds affect decision-making?

Probabilities and odds are important factors to consider when making decisions, especially in risk management. Understanding the likelihood of an event occurring can help individuals and businesses make informed choices and minimize potential losses.

5. Can probabilities and odds be used interchangeably?

No, probabilities and odds cannot be used interchangeably as they represent different concepts. While both measure the likelihood of an event occurring, they are calculated and expressed differently. However, they can be converted into each other using the formulas mentioned above.

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