place your bets – the rest of the conversation

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This statement is a contradiction …While it is true that the probability of seeing 100 consecutive red outcomes is exceedingly small (assuming a fair wheel), this does not change the fact that each individual spin still carries the same 50/50 odds.

ChatGPT said:

ChatGPT

You’re right to point out the seeming contradiction in that statement. Let’s clarify it by breaking it down more precisely.

  1. Probability of 100 Consecutive Red Outcomes: The probability of seeing 100 consecutive red outcomes on a fair roulette wheel is indeed extremely small. Each spin has a probability of approximately 1/2 (or 18/37 in European roulette, given the presence of a green zero) of landing on red. To calculate the probability of seeing 100 consecutive red spins, we would multiply the probability for each spin:(12)100≈7.9×10−31\left(\frac{1}{2}\right)^{100} \approx 7.9 \times 10^{-31}(21​)100≈7.9×10−31This is an astronomically small number, meaning that the chance of seeing 100 red outcomes in a row is extraordinarily unlikely.
  2. Each Individual Spin is Still Independent: The key to understanding the second part of the statement is to recognize that past spins have no effect on future spins. Even though the event of 100 consecutive reds is extremely rare, once it has already occurred, the outcome of the next spin is still independent of the previous ones.This means that for the 101st spin, the probability of landing on red or black remains approximately 50/50 (again, slightly less due to the presence of the green zero). The roulette wheel does not “remember” the previous 100 spins; thus, the statistical chance for red or black on the 101st spin is the same as for any other individual spin.

Clarifying the Apparent Contradiction

The confusion arises when we conflate the probability of seeing 100 consecutive red spins with the probability of the next spin being red after 100 reds have already occurred. The former is a very unlikely event (which has already happened), while the latter is just another independent spin with the same roughly 50/50 odds.

The statement should be understood as follows:

  • Before the 100 spins happen, the probability of observing 100 consecutive reds is minuscule.
  • After the 100 spins have occurred, the 101st spin is still an independent event, so the probability of landing on red or black remains close to 50/50.

This is a common source of confusion when reasoning about rare sequences in random processes. It highlights the distinction between understanding long sequences (which are rare) and understanding that individual events within those sequences remain independent.

4o

You said:

if each spin is independent of all of the other spins, then how could you say that the probability of 100 red spins is exceedingly small when that probability is in fact a compilation of each independent spin

ChatGPT said:

ChatGPT

Great question! You’re absolutely right in pointing out the key issue: if each spin is independent, then why do we say that the probability of 100 red spins in a row is “exceedingly small”? The answer lies in how we calculate joint probabilities for sequences of independent events and how those differ from the probability of each individual event.

Let’s break this down step by step:

1. Individual Spin Probability (Independent Events)

Each spin of a fair roulette wheel is an independent event. For simplicity, let’s assume we’re ignoring the green zero and focusing only on red and black, which gives approximately a 50/50 chance of landing on red or black. The probability of landing on red in one spin is:P(Red on one spin)=12P(\text{Red on one spin}) = \frac{1}{2}P(Red on one spin)=21​

This means that for each spin, there is a 50% chance of landing on red. This probability does not change for any future spins, regardless of what has happened in the past.

2. Probability of a Sequence of Spins (Joint Probability)

While each spin is independent, the probability of a specific sequence of events happening (such as getting red multiple times in a row) requires us to multiply the probabilities of the individual events.

For example, if we want to know the probability of getting two red outcomes in a row, we calculate the joint probability by multiplying the probability of red on the first spin by the probability of red on the second spin:P(Two Reds in a row)=12×12=14P(\text{Two Reds in a row}) = \frac{1}{2} \times \frac{1}{2} = \frac{1}{4}P(Two Reds in a row)=21​×21​=41​

This principle applies to any number of spins. To find the probability of getting 100 consecutive red spins, we multiply the probability of landing on red for each individual spin:P(100 Reds in a row)=(12)100≈7.9×10−31P(\text{100 Reds in a row}) = \left(\frac{1}{2}\right)^{100} \approx 7.9 \times 10^{-31}P(100 Reds in a row)=(21​)100≈7.9×10−31

This number is incredibly small, meaning that the chance of seeing 100 consecutive red spins is exceedingly unlikely, even though each individual spin has a 50/50 probability.

3. Reconciling Independence and Sequence Probability

Here’s the key distinction: while each individual spin is independent and has the same probability (1/2) of landing on red, the probability of observing a specific sequence of outcomes (such as 100 red spins in a row) involves compounding the individual probabilities. The more outcomes you string together, the smaller the probability of that entire sequence happening.

So while the probability of a single spin landing on red is always 1/2, the probability of a long sequence of specific outcomes is much smaller because it reflects the probability of each spin in that sequence being red, one after the other.

4. Why This Matters

When we say “the probability of 100 consecutive red spins is exceedingly small,” we are referring to the likelihood of observing this specific sequence of 100 spins before any of them have occurred. However, once you’ve seen 100 red spins in a row, that has already happened, and the 101st spin remains an independent event with a 50/50 chance of landing on red or black.

It’s important to distinguish between:

  • The probability of an event happening in the future (such as getting 100 consecutive reds),
  • The probability of a single event within that sequence (which is always 50/50), and
  • The fact that once the 100 red outcomes have occurred, they no longer influence the probability of the next spin.

Summary

  • Each spin is independent and has a probability of 1/2 of being red.
  • The probability of getting a specific sequence of 100 red spins is the product of each individual spin’s probability, which is very small.
  • Independence means that even after observing 100 reds in a row, the 101st spin is still 50/50.

So, while the probability of 100 consecutive red spins before it happens is small, this doesn’t affect the odds of future spins, which remain independent.

4o

You said:

The probability of getting a specific sequence of 100 red spins is the product of each individual spin’s probability, which is very small….his statement implies that each spin “knows about” the results of every other spin

ChatGPT said:

ChatGPT

I see where the confusion arises. You’re absolutely right to challenge the implication that if we calculate the probability of a sequence of spins, it might seem as though the spins “know” about each other. However, the truth is that each individual spin does not “know” about the results of the other spins. Each spin is independent, and the probability for each spin remains the same, regardless of the outcome of previous spins.

The key to resolving this confusion lies in understanding how joint probabilities work for independent events versus how individual probabilities function.

1. Independence of Individual Spins

Each spin of the roulette wheel is an independent event, meaning that no spin influences the outcome of any other spin. The wheel has no memory, and the physical process behind each spin is unaffected by previous outcomes.

Thus, for any single spin, the probability of landing on red remains:P(Red on one spin)=12P(\text{Red on one spin}) = \frac{1}{2}P(Red on one spin)=21​

Whether the wheel has landed on red 1 time, 10 times, or 100 times in the past, this probability remains the same for any future spin.

2. Joint Probability of a Sequence of Independent Events

When we calculate the probability of a sequence of outcomes (e.g., 100 consecutive reds), we are not saying that the spins are somehow connected. Instead, we are using a statistical tool known as multiplication of independent probabilities to determine how likely it is that a specific pattern or sequence of outcomes will occur.

For example, the probability of getting two reds in a row is:P(Two Reds in a row)=P(Red on the first spin)×P(Red on the second spin)=12×12=14P(\text{Two Reds in a row}) = P(\text{Red on the first spin}) \times P(\text{Red on the second spin}) = \frac{1}{2} \times \frac{1}{2} = \frac{1}{4}P(Two Reds in a row)=P(Red on the first spin)×P(Red on the second spin)=21​×21​=41​

Here’s the critical point: the multiplication of probabilities doesn’t imply that the outcomes are dependent on each other. It’s simply a method to calculate the chance of a specific combination of independent events happening in sequence. Each spin still happens independently, and the outcome of one does not affect the others.

When you calculate the probability of a specific sequence, such as 100 reds in a row:P(100 Reds in a row)=(12)100P(\text{100 Reds in a row}) = \left(\frac{1}{2}\right)^{100}P(100 Reds in a row)=(21​)100

You’re determining how likely it is to see this exact pattern from the very first spin to the 100th spin. But crucially, each spin’s probability remains 1/2 at the time of the spin. The outcome of one spin doesn’t “know” about the others.

3. Why the Joint Probability Is Small

The reason the joint probability of 100 consecutive reds is so small is that getting this exact pattern involves repeatedly hitting a 50/50 chance for red, one spin after another. It’s like flipping a coin 100 times and getting heads every single time. Each coin flip is still 50/50, but as you continue flipping, the probability of seeing a long, unbroken streak of heads decreases.

This doesn’t mean that the spins are somehow “aware” of the previous outcomes. It just means that getting such a long string of the same outcome is statistically unlikely because it requires repeating a rare event (red on a given spin) multiple times in succession.

4. What Happens After the Sequence

Now, after you’ve seen 100 red outcomes, you might feel that the next spin is somehow influenced by this streak, but that’s not true. The wheel is still operating with the same 50/50 chance for red or black on the 101st spin. The 101st spin has no connection to the previous spins, and the probability remains:P(Red on 101st spin)=12P(\text{Red on 101st spin}) = \frac{1}{2}P(Red on 101st spin)=21​

Even though the joint probability of seeing 100 consecutive reds was very small, that doesn’t change the fact that each individual spin was independent. Once the 100 reds have happened, they are in the past, and the next spin is still governed by the same odds.

Conclusion: Independence and Sequences

In summary, calculating the probability of a sequence of events doesn’t imply that the events “know” about each other. Each spin is independent, and the probability of each spin remains 50/50, regardless of previous outcomes. The small probability of a sequence of spins (like 100 reds in a row) reflects the unlikelihood of seeing that exact pattern, but it doesn’t mean the spins are dependent on one another. The concept of independence remains intact at all times.

4o

You said:

The small probability of a sequence of spins (like 100 reds in a row) reflects the unlikelihood of seeing that exact pattern,..the “pattern” implies event interdependence because a pattern is inherently non-independent

ChatGPT said:

ChatGPT

You’re raising an insightful point regarding the word “pattern” and how it might imply interdependence. Let’s explore this further and clear up the potential misunderstanding, as it’s easy to conflate the terms used in probability theory with how we understand them in everyday language.

In probability theory, we can calculate the likelihood of seeing a specific sequence of outcomes, but this does not imply that the events are dependent. This is a subtle but important distinction. Let’s examine this in more detail.

1. Independent Events and Patterns

A pattern, in the everyday sense, might suggest some kind of regularity, order, or connection between outcomes—this could indeed imply interdependence if we were talking about systems where past events influence future events. However, in the context of independent events like spins on a roulette wheel, a “pattern” is simply the result of an improbable string of outcomes happening in sequence. The outcomes are not connected, but when a specific string of results occurs, we might perceive it as a pattern.

For example:

  • In a sequence of coin flips, getting 10 heads in a row might feel like a “pattern.”
  • However, the process by which each flip occurs is still independent of the others.

The term “pattern” here is a descriptive label for an unlikely sequence that arises purely by chance in a system of independent events. It doesn’t mean the events are interdependent or that one event influences another.

2. Joint Probability vs. Independence

When calculating the probability of a sequence of events—such as 100 reds in a row—we are determining the likelihood of seeing this specific combination of independent outcomes. This involves multiplying the probabilities of each individual spin, which remain independent.

Let’s walk through the mechanics:

  • The probability of getting red on one spin is P(Red)=12P(\text{Red}) = \frac{1}{2}P(Red)=21​.
  • To find the probability of getting 100 consecutive reds, we multiply the probability for each independent event:

P(100 Reds)=(12)100P(\text{100 Reds}) = \left(\frac{1}{2}\right)^{100}P(100 Reds)=(21​)100

This joint probability calculation doesn’t imply interdependence; it’s simply a way of calculating the likelihood of seeing a specific combination of independent outcomes. The fact that the resulting probability is small only reflects how rare it is to see such a long sequence of identical outcomes.

Crucially, the small probability of seeing 100 reds in a row does not mean that the events depend on each other. The probability calculation reflects how unlikely it is to get that exact sequence, but each spin remains independent.

3. Why Patterns Appear in Randomness

In a sequence of independent events, patterns can and do occur by chance, but this doesn’t mean the events are dependent. Humans have a natural tendency to perceive patterns in random data—a phenomenon known as apophenia or pattern recognition bias. When we see something like 100 consecutive red outcomes, we might instinctively think there’s some hidden cause or interconnection between the events, but statistically, this is not the case.

4. Patterns in a Statistical Sense

In probability theory, when we refer to the probability of a specific sequence, we might colloquially call this a “pattern,” but it’s important to remember that this pattern is just a specific set of independent outcomes. The word “pattern” here doesn’t carry the connotation of interdependence that it might in other contexts. It simply means we’re calculating the likelihood of seeing this particular string of results.

5. Summary: Independence vs. Perceived Patterns

  • Each spin is independent: The outcome of one spin has no influence on the next. The probability of landing on red for each spin remains 50/50.
  • Joint probability of sequences: When calculating the probability of seeing a specific sequence (like 100 reds), we multiply the individual probabilities. This is not because the events are dependent, but because we’re calculating the likelihood of this exact combination of independent events happening.
  • “Pattern” doesn’t mean dependence: In everyday language, “pattern” might imply some kind of regularity or interconnection. In the context of probability, it just refers to a specific sequence of independent outcomes. Seeing a pattern does not imply that the events are interdependent.

Conclusion

When we talk about the probability of a “pattern” like 100 consecutive reds, we’re simply describing a rare sequence of independent events. The fact that this sequence is unlikely doesn’t mean the individual events are interdependent—it just means that long sequences of identical outcomes are rare in systems where each event is independent.

4o


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