Chances of rolling “Snake Eyes†at least once in a series of rolls.
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So I know that if you roll a standard pair of dice, your chances of getting Snake Eyes (double 1s) is $1$ in $36$. What I'm not sure of is how to do the math to figure out your chances of rolling Snake Eyes at least once during a series of rolls. I know if I roll the dice $36$ times it won't lead to a $100%$ chance of rolling Snake Eyes, and while I imagine it's in the upper nineties, I'd like to figure out exactly how unlikely it is.
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So I know that if you roll a standard pair of dice, your chances of getting Snake Eyes (double 1s) is $1$ in $36$. What I'm not sure of is how to do the math to figure out your chances of rolling Snake Eyes at least once during a series of rolls. I know if I roll the dice $36$ times it won't lead to a $100%$ chance of rolling Snake Eyes, and while I imagine it's in the upper nineties, I'd like to figure out exactly how unlikely it is.
probability dice
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
So I know that if you roll a standard pair of dice, your chances of getting Snake Eyes (double 1s) is $1$ in $36$. What I'm not sure of is how to do the math to figure out your chances of rolling Snake Eyes at least once during a series of rolls. I know if I roll the dice $36$ times it won't lead to a $100%$ chance of rolling Snake Eyes, and while I imagine it's in the upper nineties, I'd like to figure out exactly how unlikely it is.
probability dice
So I know that if you roll a standard pair of dice, your chances of getting Snake Eyes (double 1s) is $1$ in $36$. What I'm not sure of is how to do the math to figure out your chances of rolling Snake Eyes at least once during a series of rolls. I know if I roll the dice $36$ times it won't lead to a $100%$ chance of rolling Snake Eyes, and while I imagine it's in the upper nineties, I'd like to figure out exactly how unlikely it is.
probability dice
probability dice
edited 28 mins ago
Especially Lime
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aslum
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3 Answers
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If you roll $n$ times, then the probability of rolling snake eyes at least once is $1-left(frac3536right)^n$, as you either roll snake eyes at least once or not at all (so the probability of these two events should sum to $1$), and the probability of never rolling snake eyes is the same as requiring that you roll one of the other $35$ possible outcomes on each roll.
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The probability of hitting it at least once is $1$ minus the probabilty of never hitting it.
Every time you roll the dices you have a $35/36$ chance of not hitting it. If you roll the dices $n$ times, then the only case where you have never hit it, is when you have not hit it every single time.
The probabilty of not hitting with $2$ rolls is thus $35/36times 35/36$, the probabilty of not hitting with $3$ rolls is $35/36times 35/36times 35/36=(35/36)^3$ and so on till $(35/36)^n$.
Thus the probability of hitting it at least once is $1-(35/36)^n$ where $n$ is the number of throws.
After $164$ throws, the probability of hitting it at least once is $99%$
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The other answers explain the general formula for the probability of never rolling snake eyes in a series of $n$ rolls.
However, you also ask specifically about the case $n=36$, i.e. if you have a $1$ in $k$ chance of success, what is your chance of getting at least one success in $k$ trials? It turns out that the answer to this question is quite similar for any reasonably large value of $k$.
It is $1-big(1-frac1kbig)^k$, and $big(1-frac1kbig)^k$ converges to $e^-1$. So the probability will be about $1-e^-1approx 63.2%$, and this approximation will get better the larger $k$ is. (For $k=36$ the real answer is $63.7%$.)
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
2
down vote
If you roll $n$ times, then the probability of rolling snake eyes at least once is $1-left(frac3536right)^n$, as you either roll snake eyes at least once or not at all (so the probability of these two events should sum to $1$), and the probability of never rolling snake eyes is the same as requiring that you roll one of the other $35$ possible outcomes on each roll.
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
2
down vote
If you roll $n$ times, then the probability of rolling snake eyes at least once is $1-left(frac3536right)^n$, as you either roll snake eyes at least once or not at all (so the probability of these two events should sum to $1$), and the probability of never rolling snake eyes is the same as requiring that you roll one of the other $35$ possible outcomes on each roll.
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
2
down vote
up vote
2
down vote
If you roll $n$ times, then the probability of rolling snake eyes at least once is $1-left(frac3536right)^n$, as you either roll snake eyes at least once or not at all (so the probability of these two events should sum to $1$), and the probability of never rolling snake eyes is the same as requiring that you roll one of the other $35$ possible outcomes on each roll.
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
If you roll $n$ times, then the probability of rolling snake eyes at least once is $1-left(frac3536right)^n$, as you either roll snake eyes at least once or not at all (so the probability of these two events should sum to $1$), and the probability of never rolling snake eyes is the same as requiring that you roll one of the other $35$ possible outcomes on each roll.
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 46 mins ago
Sam Streeter
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313
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Sam Streeter is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
add a comment |Â
up vote
2
down vote
The probability of hitting it at least once is $1$ minus the probabilty of never hitting it.
Every time you roll the dices you have a $35/36$ chance of not hitting it. If you roll the dices $n$ times, then the only case where you have never hit it, is when you have not hit it every single time.
The probabilty of not hitting with $2$ rolls is thus $35/36times 35/36$, the probabilty of not hitting with $3$ rolls is $35/36times 35/36times 35/36=(35/36)^3$ and so on till $(35/36)^n$.
Thus the probability of hitting it at least once is $1-(35/36)^n$ where $n$ is the number of throws.
After $164$ throws, the probability of hitting it at least once is $99%$
add a comment |Â
up vote
2
down vote
The probability of hitting it at least once is $1$ minus the probabilty of never hitting it.
Every time you roll the dices you have a $35/36$ chance of not hitting it. If you roll the dices $n$ times, then the only case where you have never hit it, is when you have not hit it every single time.
The probabilty of not hitting with $2$ rolls is thus $35/36times 35/36$, the probabilty of not hitting with $3$ rolls is $35/36times 35/36times 35/36=(35/36)^3$ and so on till $(35/36)^n$.
Thus the probability of hitting it at least once is $1-(35/36)^n$ where $n$ is the number of throws.
After $164$ throws, the probability of hitting it at least once is $99%$
add a comment |Â
up vote
2
down vote
up vote
2
down vote
The probability of hitting it at least once is $1$ minus the probabilty of never hitting it.
Every time you roll the dices you have a $35/36$ chance of not hitting it. If you roll the dices $n$ times, then the only case where you have never hit it, is when you have not hit it every single time.
The probabilty of not hitting with $2$ rolls is thus $35/36times 35/36$, the probabilty of not hitting with $3$ rolls is $35/36times 35/36times 35/36=(35/36)^3$ and so on till $(35/36)^n$.
Thus the probability of hitting it at least once is $1-(35/36)^n$ where $n$ is the number of throws.
After $164$ throws, the probability of hitting it at least once is $99%$
The probability of hitting it at least once is $1$ minus the probabilty of never hitting it.
Every time you roll the dices you have a $35/36$ chance of not hitting it. If you roll the dices $n$ times, then the only case where you have never hit it, is when you have not hit it every single time.
The probabilty of not hitting with $2$ rolls is thus $35/36times 35/36$, the probabilty of not hitting with $3$ rolls is $35/36times 35/36times 35/36=(35/36)^3$ and so on till $(35/36)^n$.
Thus the probability of hitting it at least once is $1-(35/36)^n$ where $n$ is the number of throws.
After $164$ throws, the probability of hitting it at least once is $99%$
edited 41 mins ago
answered 49 mins ago
b00n heT
9,11011833
9,11011833
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up vote
2
down vote
The other answers explain the general formula for the probability of never rolling snake eyes in a series of $n$ rolls.
However, you also ask specifically about the case $n=36$, i.e. if you have a $1$ in $k$ chance of success, what is your chance of getting at least one success in $k$ trials? It turns out that the answer to this question is quite similar for any reasonably large value of $k$.
It is $1-big(1-frac1kbig)^k$, and $big(1-frac1kbig)^k$ converges to $e^-1$. So the probability will be about $1-e^-1approx 63.2%$, and this approximation will get better the larger $k$ is. (For $k=36$ the real answer is $63.7%$.)
add a comment |Â
up vote
2
down vote
The other answers explain the general formula for the probability of never rolling snake eyes in a series of $n$ rolls.
However, you also ask specifically about the case $n=36$, i.e. if you have a $1$ in $k$ chance of success, what is your chance of getting at least one success in $k$ trials? It turns out that the answer to this question is quite similar for any reasonably large value of $k$.
It is $1-big(1-frac1kbig)^k$, and $big(1-frac1kbig)^k$ converges to $e^-1$. So the probability will be about $1-e^-1approx 63.2%$, and this approximation will get better the larger $k$ is. (For $k=36$ the real answer is $63.7%$.)
add a comment |Â
up vote
2
down vote
up vote
2
down vote
The other answers explain the general formula for the probability of never rolling snake eyes in a series of $n$ rolls.
However, you also ask specifically about the case $n=36$, i.e. if you have a $1$ in $k$ chance of success, what is your chance of getting at least one success in $k$ trials? It turns out that the answer to this question is quite similar for any reasonably large value of $k$.
It is $1-big(1-frac1kbig)^k$, and $big(1-frac1kbig)^k$ converges to $e^-1$. So the probability will be about $1-e^-1approx 63.2%$, and this approximation will get better the larger $k$ is. (For $k=36$ the real answer is $63.7%$.)
The other answers explain the general formula for the probability of never rolling snake eyes in a series of $n$ rolls.
However, you also ask specifically about the case $n=36$, i.e. if you have a $1$ in $k$ chance of success, what is your chance of getting at least one success in $k$ trials? It turns out that the answer to this question is quite similar for any reasonably large value of $k$.
It is $1-big(1-frac1kbig)^k$, and $big(1-frac1kbig)^k$ converges to $e^-1$. So the probability will be about $1-e^-1approx 63.2%$, and this approximation will get better the larger $k$ is. (For $k=36$ the real answer is $63.7%$.)
answered 29 mins ago
Especially Lime
19.8k22353
19.8k22353
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