What don't I get about coin tossing?

  • Context: High School 
  • Thread starter Thread starter Intervenient
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the probabilities associated with multiple coin tosses, specifically focusing on the probability of obtaining a specific sequence of heads and tails over five tosses. Participants explore the concepts of independence in probability and how it relates to the outcomes of coin tosses.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant notes that the probability of getting heads five times in a row is calculated as .5^5, or 1/32, but questions the relationship between this probability and the equal chance of heads or tails on each toss.
  • Another participant agrees that the probability of any specific sequence of five tosses, such as "head, head, head, head, head," is the same as any other specific sequence, reinforcing that there are 32 possible outcomes, each equally likely.
  • A third participant emphasizes that probability is a measure of uncertainty and clarifies that once a sequence is generated, the probability of that specific sequence occurring is no longer relevant, as it is now a certainty (probability of 1) that it has occurred.
  • Another participant reiterates that the probability is distributed over 32 outcomes rather than just 2, leading to the conclusion of 1/32 for any specific sequence.

Areas of Agreement / Disagreement

Participants generally agree on the calculation of the probability for specific sequences of coin tosses and the concept of independence. However, there is some uncertainty regarding the interpretation of probability before and after the outcomes are realized.

Contextual Notes

Limitations include the participants' varying levels of understanding of probability concepts, particularly regarding the implications of independence and the nature of probability before and after events occur.

Who May Find This Useful

This discussion may be useful for individuals seeking to understand basic probability concepts, particularly in relation to independent events and the interpretation of outcomes in probability theory.

Intervenient
Messages
48
Reaction score
0
I've never had a basic probability course before, so I've only been able to get my hands on a few materials relating to the subject.So let's say there are 5 coin tosses. The probability of getting heads 5 times in a row is .5^5, or 1/32.

But since coin tosses are independent of each other, each time the coin is tossed, there's an equal chance of it being heads, as it is tails. So shouldn't the probability always be .5? Doesn't 5 heads in a row, have the same probability of heads, tails, heads ,tails, heads?

What piece of the puzzle aren't I getting :/
Edit: There are 32 different possible outcomes, hence 1/32. I get that because it's independent it's either heads or tails, and not due up. So I guess the question is how they relate.
 
Last edited:
Physics news on Phys.org
The prob of "head, head, head, head, head" is exactly the same as "head, tail, head, tail, head" which in turn is the same as "head, head, tail, head, head" which is the same as "tail, tail, tail, tail, tail" and so on.

There are 32 possible results to five coin tosses, and each is just as likely as the rest. They must add up to 1. So the prob must be 1/32.
 
The important point is that probability is a measure of uncertainty. Any particular sequence of 5 tosses, predicted in advance, has a 1/32 probability of occurring assuming a fair coin. After the sequence is generated, it no longer makes sense to talk about the probability of that sequence. The probability of an event that has already occurred is 1. The probability of generating the same sequence again is 1/32.
 
Last edited:
Like pwsnafu said, there are 32 states instead of 2, so the probability is distributed over 32 (i.e. 1/32) instead of 2 (1/2).
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 21 ·
Replies
21
Views
3K
  • · Replies 57 ·
2
Replies
57
Views
7K
  • · Replies 20 ·
Replies
20
Views
6K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 126 ·
5
Replies
126
Views
9K
  • · Replies 45 ·
2
Replies
45
Views
6K
  • · Replies 5 ·
Replies
5
Views
2K