Asymptotic growth of translation in random walk.












-1












$begingroup$


Let's consider a random walk with translation $$F(N)=sum_{n=1}^{N}X(n)$$
Where $X(n)$ is a random variable distribiuted independently and equal to $0$ or $1$.



What is asymptotic growth of $F(N)$?



i.e.



I am looking for function $f$ which satisfy:$$F(N)=O(f(N))$$
Is this true that $f(N)=N^{0.5}$



I hope that someone will help me.










share|cite|improve this question









$endgroup$












  • $begingroup$
    To be clear, $X$ has a probability of $1/2$ being $0$ and $1/2$ being $1$, correct? It's not really clear from your wording.
    $endgroup$
    – Noble Mushtak
    Dec 28 '18 at 21:35
















-1












$begingroup$


Let's consider a random walk with translation $$F(N)=sum_{n=1}^{N}X(n)$$
Where $X(n)$ is a random variable distribiuted independently and equal to $0$ or $1$.



What is asymptotic growth of $F(N)$?



i.e.



I am looking for function $f$ which satisfy:$$F(N)=O(f(N))$$
Is this true that $f(N)=N^{0.5}$



I hope that someone will help me.










share|cite|improve this question









$endgroup$












  • $begingroup$
    To be clear, $X$ has a probability of $1/2$ being $0$ and $1/2$ being $1$, correct? It's not really clear from your wording.
    $endgroup$
    – Noble Mushtak
    Dec 28 '18 at 21:35














-1












-1








-1





$begingroup$


Let's consider a random walk with translation $$F(N)=sum_{n=1}^{N}X(n)$$
Where $X(n)$ is a random variable distribiuted independently and equal to $0$ or $1$.



What is asymptotic growth of $F(N)$?



i.e.



I am looking for function $f$ which satisfy:$$F(N)=O(f(N))$$
Is this true that $f(N)=N^{0.5}$



I hope that someone will help me.










share|cite|improve this question









$endgroup$




Let's consider a random walk with translation $$F(N)=sum_{n=1}^{N}X(n)$$
Where $X(n)$ is a random variable distribiuted independently and equal to $0$ or $1$.



What is asymptotic growth of $F(N)$?



i.e.



I am looking for function $f$ which satisfy:$$F(N)=O(f(N))$$
Is this true that $f(N)=N^{0.5}$



I hope that someone will help me.







asymptotics random-walk






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 28 '18 at 21:30









mkultramkultra

1038




1038












  • $begingroup$
    To be clear, $X$ has a probability of $1/2$ being $0$ and $1/2$ being $1$, correct? It's not really clear from your wording.
    $endgroup$
    – Noble Mushtak
    Dec 28 '18 at 21:35


















  • $begingroup$
    To be clear, $X$ has a probability of $1/2$ being $0$ and $1/2$ being $1$, correct? It's not really clear from your wording.
    $endgroup$
    – Noble Mushtak
    Dec 28 '18 at 21:35
















$begingroup$
To be clear, $X$ has a probability of $1/2$ being $0$ and $1/2$ being $1$, correct? It's not really clear from your wording.
$endgroup$
– Noble Mushtak
Dec 28 '18 at 21:35




$begingroup$
To be clear, $X$ has a probability of $1/2$ being $0$ and $1/2$ being $1$, correct? It's not really clear from your wording.
$endgroup$
– Noble Mushtak
Dec 28 '18 at 21:35










1 Answer
1






active

oldest

votes


















1












$begingroup$

First, notice that $mu_X=frac 1 2$ and $sigma_X=frac 1 2(0-frac 1 2)^2+frac 1 2(1-frac 1 2)^2=frac 1 4$.



Let's consider:



$$G(N)=frac{F(N)}{N}=frac 1 N sum_{n=1}^N X(n)$$



By the Central Limit Theorem, as $Nrightarrow infty $, $G$ becomes normally distributed with $mu_G=mu_X=frac 1 2$ and $sigma_G=frac{sigma_X}{sqrt N}=frac{1}{4sqrt N}$



Now, $F=NG$. Therefore, as $Nrightarrow infty$, $F$ becomes normally distributed with $mu_F=Nmu_G=frac N 2$ and $sigma_F=Nsigma_G=frac{sqrt N}{4}$. Therefore, the expected value of $F$ is $O(N)$ and the standard deviation of $F$ is $O(sqrt N)$.



In short, in the average-case scenario, $F$ is $O(N)$. Also, in the worst-case scenario, $F=N$, so $F$ is $O(N)$ in worst-case scenario as well.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    But how the expected value determines "big O" notation?
    $endgroup$
    – mkultra
    Dec 29 '18 at 12:20










  • $begingroup$
    @mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
    $endgroup$
    – Noble Mushtak
    Dec 29 '18 at 15:09












Your Answer








StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3055308%2fasymptotic-growth-of-translation-in-random-walk%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









1












$begingroup$

First, notice that $mu_X=frac 1 2$ and $sigma_X=frac 1 2(0-frac 1 2)^2+frac 1 2(1-frac 1 2)^2=frac 1 4$.



Let's consider:



$$G(N)=frac{F(N)}{N}=frac 1 N sum_{n=1}^N X(n)$$



By the Central Limit Theorem, as $Nrightarrow infty $, $G$ becomes normally distributed with $mu_G=mu_X=frac 1 2$ and $sigma_G=frac{sigma_X}{sqrt N}=frac{1}{4sqrt N}$



Now, $F=NG$. Therefore, as $Nrightarrow infty$, $F$ becomes normally distributed with $mu_F=Nmu_G=frac N 2$ and $sigma_F=Nsigma_G=frac{sqrt N}{4}$. Therefore, the expected value of $F$ is $O(N)$ and the standard deviation of $F$ is $O(sqrt N)$.



In short, in the average-case scenario, $F$ is $O(N)$. Also, in the worst-case scenario, $F=N$, so $F$ is $O(N)$ in worst-case scenario as well.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    But how the expected value determines "big O" notation?
    $endgroup$
    – mkultra
    Dec 29 '18 at 12:20










  • $begingroup$
    @mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
    $endgroup$
    – Noble Mushtak
    Dec 29 '18 at 15:09
















1












$begingroup$

First, notice that $mu_X=frac 1 2$ and $sigma_X=frac 1 2(0-frac 1 2)^2+frac 1 2(1-frac 1 2)^2=frac 1 4$.



Let's consider:



$$G(N)=frac{F(N)}{N}=frac 1 N sum_{n=1}^N X(n)$$



By the Central Limit Theorem, as $Nrightarrow infty $, $G$ becomes normally distributed with $mu_G=mu_X=frac 1 2$ and $sigma_G=frac{sigma_X}{sqrt N}=frac{1}{4sqrt N}$



Now, $F=NG$. Therefore, as $Nrightarrow infty$, $F$ becomes normally distributed with $mu_F=Nmu_G=frac N 2$ and $sigma_F=Nsigma_G=frac{sqrt N}{4}$. Therefore, the expected value of $F$ is $O(N)$ and the standard deviation of $F$ is $O(sqrt N)$.



In short, in the average-case scenario, $F$ is $O(N)$. Also, in the worst-case scenario, $F=N$, so $F$ is $O(N)$ in worst-case scenario as well.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    But how the expected value determines "big O" notation?
    $endgroup$
    – mkultra
    Dec 29 '18 at 12:20










  • $begingroup$
    @mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
    $endgroup$
    – Noble Mushtak
    Dec 29 '18 at 15:09














1












1








1





$begingroup$

First, notice that $mu_X=frac 1 2$ and $sigma_X=frac 1 2(0-frac 1 2)^2+frac 1 2(1-frac 1 2)^2=frac 1 4$.



Let's consider:



$$G(N)=frac{F(N)}{N}=frac 1 N sum_{n=1}^N X(n)$$



By the Central Limit Theorem, as $Nrightarrow infty $, $G$ becomes normally distributed with $mu_G=mu_X=frac 1 2$ and $sigma_G=frac{sigma_X}{sqrt N}=frac{1}{4sqrt N}$



Now, $F=NG$. Therefore, as $Nrightarrow infty$, $F$ becomes normally distributed with $mu_F=Nmu_G=frac N 2$ and $sigma_F=Nsigma_G=frac{sqrt N}{4}$. Therefore, the expected value of $F$ is $O(N)$ and the standard deviation of $F$ is $O(sqrt N)$.



In short, in the average-case scenario, $F$ is $O(N)$. Also, in the worst-case scenario, $F=N$, so $F$ is $O(N)$ in worst-case scenario as well.






share|cite|improve this answer









$endgroup$



First, notice that $mu_X=frac 1 2$ and $sigma_X=frac 1 2(0-frac 1 2)^2+frac 1 2(1-frac 1 2)^2=frac 1 4$.



Let's consider:



$$G(N)=frac{F(N)}{N}=frac 1 N sum_{n=1}^N X(n)$$



By the Central Limit Theorem, as $Nrightarrow infty $, $G$ becomes normally distributed with $mu_G=mu_X=frac 1 2$ and $sigma_G=frac{sigma_X}{sqrt N}=frac{1}{4sqrt N}$



Now, $F=NG$. Therefore, as $Nrightarrow infty$, $F$ becomes normally distributed with $mu_F=Nmu_G=frac N 2$ and $sigma_F=Nsigma_G=frac{sqrt N}{4}$. Therefore, the expected value of $F$ is $O(N)$ and the standard deviation of $F$ is $O(sqrt N)$.



In short, in the average-case scenario, $F$ is $O(N)$. Also, in the worst-case scenario, $F=N$, so $F$ is $O(N)$ in worst-case scenario as well.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Dec 28 '18 at 21:43









Noble MushtakNoble Mushtak

15.4k1835




15.4k1835












  • $begingroup$
    But how the expected value determines "big O" notation?
    $endgroup$
    – mkultra
    Dec 29 '18 at 12:20










  • $begingroup$
    @mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
    $endgroup$
    – Noble Mushtak
    Dec 29 '18 at 15:09


















  • $begingroup$
    But how the expected value determines "big O" notation?
    $endgroup$
    – mkultra
    Dec 29 '18 at 12:20










  • $begingroup$
    @mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
    $endgroup$
    – Noble Mushtak
    Dec 29 '18 at 15:09
















$begingroup$
But how the expected value determines "big O" notation?
$endgroup$
– mkultra
Dec 29 '18 at 12:20




$begingroup$
But how the expected value determines "big O" notation?
$endgroup$
– mkultra
Dec 29 '18 at 12:20












$begingroup$
@mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
$endgroup$
– Noble Mushtak
Dec 29 '18 at 15:09




$begingroup$
@mkultra Well, really the worst-case scenario determines big O notation, but sometimes, you will see people talk about average-case complexity as well: en.wikipedia.org/wiki/Average-case_complexity
$endgroup$
– Noble Mushtak
Dec 29 '18 at 15:09


















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3055308%2fasymptotic-growth-of-translation-in-random-walk%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

How to change which sound is reproduced for terminal bell?

Title Spacing in Bjornstrup Chapter, Removing Chapter Number From Contents

Can I use Tabulator js library in my java Spring + Thymeleaf project?