What is the expectation of $X$?
0
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Let the random variable $X$ represent the number of times a fair coin needs to be tossed till two consecutive heads appear for the first time. The expectation of $X$ is ?
probability random-variables expected-value
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
asked Jan 5 at 6:33
empty-soulempty-soul
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add a comment |
0
$begingroup$
Let the random variable $X$ represent the number of times a fair coin needs to be tossed till two consecutive heads appear for the first time. The expectation of $X$ is ?
probability random-variables expected-value
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
asked Jan 5 at 6:33
empty-soulempty-soul
1
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level.
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– Clement C.
Jan 5 at 6:58
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i approached this problem as : since we need minimum 2 tosses to get two heads. starting from two tosses we get expectation as 2*(1/4) + 3*(1/8) + 4*(1/16)+ ... and so on. is this a correct way or am i doing something wrong.
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– empty-soul
Jan 5 at 7:03
2
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@empty-soul Add your working in your original post by editing it.
$endgroup$
– StubbornAtom
Jan 5 at 7:11
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@empty-soul: What tools do you have? Do you know Markov chains? Also, are you sure about your probability mass for the case when it takes 4 flips?
$endgroup$
– Michael
Jan 5 at 7:53
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anyone please post an answer.
$endgroup$
– empty-soul
Jan 5 at 16:28
add a comment |
0
0
0
$begingroup$
Let the random variable $X$ represent the number of times a fair coin needs to be tossed till two consecutive heads appear for the first time. The expectation of $X$ is ?
probability random-variables expected-value
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
asked Jan 5 at 6:33
empty-soulempty-soul
1
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
Let the random variable $X$ represent the number of times a fair coin needs to be tossed till two consecutive heads appear for the first time. The expectation of $X$ is ?
probability random-variables expected-value
probability random-variables expected-value
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
asked Jan 5 at 6:33
empty-soulempty-soul
1
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
asked Jan 5 at 6:33
empty-soulempty-soul
1
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
edited Jan 5 at 6:37
Antonios-Alexandros Robotis
9,71741640
9,71741640
asked Jan 5 at 6:33
empty-soulempty-soul
1
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Jan 5 at 6:33
empty-soulempty-soul
1
asked Jan 5 at 6:33
empty-soulempty-soul
1
1
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
empty-soul is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level.
$endgroup$
– Clement C.
Jan 5 at 6:58
$begingroup$
i approached this problem as : since we need minimum 2 tosses to get two heads. starting from two tosses we get expectation as 2*(1/4) + 3*(1/8) + 4*(1/16)+ ... and so on. is this a correct way or am i doing something wrong.
$endgroup$
– empty-soul
Jan 5 at 7:03
2
$begingroup$
@empty-soul Add your working in your original post by editing it.
$endgroup$
– StubbornAtom
Jan 5 at 7:11
$begingroup$
@empty-soul: What tools do you have? Do you know Markov chains? Also, are you sure about your probability mass for the case when it takes 4 flips?
$endgroup$
– Michael
Jan 5 at 7:53
$begingroup$
anyone please post an answer.
$endgroup$
– empty-soul
Jan 5 at 16:28
add a comment |
$begingroup$
Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level.
$endgroup$
– Clement C.
Jan 5 at 6:58
$begingroup$
i approached this problem as : since we need minimum 2 tosses to get two heads. starting from two tosses we get expectation as 2*(1/4) + 3*(1/8) + 4*(1/16)+ ... and so on. is this a correct way or am i doing something wrong.
$endgroup$
– empty-soul
Jan 5 at 7:03
2
$begingroup$
@empty-soul Add your working in your original post by editing it.
$endgroup$
– StubbornAtom
Jan 5 at 7:11
$begingroup$
@empty-soul: What tools do you have? Do you know Markov chains? Also, are you sure about your probability mass for the case when it takes 4 flips?
$endgroup$
– Michael
Jan 5 at 7:53
$begingroup$
anyone please post an answer.
$endgroup$
– empty-soul
Jan 5 at 16:28
$begingroup$
Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level.
$endgroup$
– Clement C.
Jan 5 at 6:58
$begingroup$
Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level.
$endgroup$
– Clement C.
Jan 5 at 6:58
$begingroup$
i approached this problem as : since we need minimum 2 tosses to get two heads. starting from two tosses we get expectation as 2*(1/4) + 3*(1/8) + 4*(1/16)+ ... and so on. is this a correct way or am i doing something wrong.
$endgroup$
– empty-soul
Jan 5 at 7:03
$begingroup$
i approached this problem as : since we need minimum 2 tosses to get two heads. starting from two tosses we get expectation as 2*(1/4) + 3*(1/8) + 4*(1/16)+ ... and so on. is this a correct way or am i doing something wrong.
$endgroup$
– empty-soul
Jan 5 at 7:03
2
2
$begingroup$
@empty-soul Add your working in your original post by editing it.
$endgroup$
– StubbornAtom
Jan 5 at 7:11
$begingroup$
@empty-soul Add your working in your original post by editing it.
$endgroup$
– StubbornAtom
Jan 5 at 7:11
$begingroup$
@empty-soul: What tools do you have? Do you know Markov chains? Also, are you sure about your probability mass for the case when it takes 4 flips?
$endgroup$
– Michael
Jan 5 at 7:53
$begingroup$
@empty-soul: What tools do you have? Do you know Markov chains? Also, are you sure about your probability mass for the case when it takes 4 flips?
$endgroup$
– Michael
Jan 5 at 7:53
$begingroup$
anyone please post an answer.
$endgroup$
– empty-soul
Jan 5 at 16:28
$begingroup$
anyone please post an answer.
$endgroup$
– empty-soul
Jan 5 at 16:28
add a comment |
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$begingroup$
Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level.
$endgroup$
– Clement C.
Jan 5 at 6:58
$begingroup$
i approached this problem as : since we need minimum 2 tosses to get two heads. starting from two tosses we get expectation as 2*(1/4) + 3*(1/8) + 4*(1/16)+ ... and so on. is this a correct way or am i doing something wrong.
$endgroup$
– empty-soul
Jan 5 at 7:03
2
$begingroup$
@empty-soul Add your working in your original post by editing it.
$endgroup$
– StubbornAtom
Jan 5 at 7:11
$begingroup$
@empty-soul: What tools do you have? Do you know Markov chains? Also, are you sure about your probability mass for the case when it takes 4 flips?
$endgroup$
– Michael
Jan 5 at 7:53
$begingroup$
anyone please post an answer.
$endgroup$
– empty-soul
Jan 5 at 16:28