Compute the maximum likelihood estimator for $θ$.












0












$begingroup$


Let $X_1, X_2, . . . , X_n$ be a random sample from a Bernoulli distribution with parameter $θ$. Compute the maximum likelihood estimator for $θ$.



In my opinion this is the correct way to solve it:
$L(Theta)=theta_1*(1-theta_1)*...theta_n*(1-theta_n)=theta^n*(1-theta)^n$
$l(Theta)=n*ln(theta)+n*ln(1-theta)$
$l'(theta)=frac{n}{theta}-frac{n}{1-theta}=0$, $theta=frac{1}{2}$

For the official solution it should be $frac{sum_{i=1}^nX_i}{n}$, why MLE is incorrect, where should I put the $x$ that in my solution is not present?










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    bernoulli has no pdf, calculating max with derivatives is here not possible
    $endgroup$
    – Joey Doey
    Jan 25 at 14:52








  • 1




    $begingroup$
    Your likelihood formula is wrong - your formula doesn't depend on the data that you see, only $n$. When you use the correct formula you can differentiate the log likelihood to get the MLE.
    $endgroup$
    – Alex
    Jan 25 at 15:28










  • $begingroup$
    @Alex what do you mean?
    $endgroup$
    – Luke Marci
    Jan 25 at 15:31






  • 1




    $begingroup$
    The likelihood should depend on the data you see. E.g. suppose you just had $n = 1$ and observed $X_1 = x_1$. If that was a success ($x_1 = 1$) then the likelihood would be $theta$, and if it was a failure ($x_1 = 0$) then the likelihood would be $(1 - theta)$. In the first case the MLE would be $hat{theta} = 1$ and in the second case the MLE would be $hat{theta} = 0$.
    $endgroup$
    – Alex
    Jan 25 at 15:36


















0












$begingroup$


Let $X_1, X_2, . . . , X_n$ be a random sample from a Bernoulli distribution with parameter $θ$. Compute the maximum likelihood estimator for $θ$.



In my opinion this is the correct way to solve it:
$L(Theta)=theta_1*(1-theta_1)*...theta_n*(1-theta_n)=theta^n*(1-theta)^n$
$l(Theta)=n*ln(theta)+n*ln(1-theta)$
$l'(theta)=frac{n}{theta}-frac{n}{1-theta}=0$, $theta=frac{1}{2}$

For the official solution it should be $frac{sum_{i=1}^nX_i}{n}$, why MLE is incorrect, where should I put the $x$ that in my solution is not present?










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    bernoulli has no pdf, calculating max with derivatives is here not possible
    $endgroup$
    – Joey Doey
    Jan 25 at 14:52








  • 1




    $begingroup$
    Your likelihood formula is wrong - your formula doesn't depend on the data that you see, only $n$. When you use the correct formula you can differentiate the log likelihood to get the MLE.
    $endgroup$
    – Alex
    Jan 25 at 15:28










  • $begingroup$
    @Alex what do you mean?
    $endgroup$
    – Luke Marci
    Jan 25 at 15:31






  • 1




    $begingroup$
    The likelihood should depend on the data you see. E.g. suppose you just had $n = 1$ and observed $X_1 = x_1$. If that was a success ($x_1 = 1$) then the likelihood would be $theta$, and if it was a failure ($x_1 = 0$) then the likelihood would be $(1 - theta)$. In the first case the MLE would be $hat{theta} = 1$ and in the second case the MLE would be $hat{theta} = 0$.
    $endgroup$
    – Alex
    Jan 25 at 15:36
















0












0








0





$begingroup$


Let $X_1, X_2, . . . , X_n$ be a random sample from a Bernoulli distribution with parameter $θ$. Compute the maximum likelihood estimator for $θ$.



In my opinion this is the correct way to solve it:
$L(Theta)=theta_1*(1-theta_1)*...theta_n*(1-theta_n)=theta^n*(1-theta)^n$
$l(Theta)=n*ln(theta)+n*ln(1-theta)$
$l'(theta)=frac{n}{theta}-frac{n}{1-theta}=0$, $theta=frac{1}{2}$

For the official solution it should be $frac{sum_{i=1}^nX_i}{n}$, why MLE is incorrect, where should I put the $x$ that in my solution is not present?










share|cite|improve this question









$endgroup$




Let $X_1, X_2, . . . , X_n$ be a random sample from a Bernoulli distribution with parameter $θ$. Compute the maximum likelihood estimator for $θ$.



In my opinion this is the correct way to solve it:
$L(Theta)=theta_1*(1-theta_1)*...theta_n*(1-theta_n)=theta^n*(1-theta)^n$
$l(Theta)=n*ln(theta)+n*ln(1-theta)$
$l'(theta)=frac{n}{theta}-frac{n}{1-theta}=0$, $theta=frac{1}{2}$

For the official solution it should be $frac{sum_{i=1}^nX_i}{n}$, why MLE is incorrect, where should I put the $x$ that in my solution is not present?







statistics






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 25 at 14:49









Luke MarciLuke Marci

856




856








  • 1




    $begingroup$
    bernoulli has no pdf, calculating max with derivatives is here not possible
    $endgroup$
    – Joey Doey
    Jan 25 at 14:52








  • 1




    $begingroup$
    Your likelihood formula is wrong - your formula doesn't depend on the data that you see, only $n$. When you use the correct formula you can differentiate the log likelihood to get the MLE.
    $endgroup$
    – Alex
    Jan 25 at 15:28










  • $begingroup$
    @Alex what do you mean?
    $endgroup$
    – Luke Marci
    Jan 25 at 15:31






  • 1




    $begingroup$
    The likelihood should depend on the data you see. E.g. suppose you just had $n = 1$ and observed $X_1 = x_1$. If that was a success ($x_1 = 1$) then the likelihood would be $theta$, and if it was a failure ($x_1 = 0$) then the likelihood would be $(1 - theta)$. In the first case the MLE would be $hat{theta} = 1$ and in the second case the MLE would be $hat{theta} = 0$.
    $endgroup$
    – Alex
    Jan 25 at 15:36
















  • 1




    $begingroup$
    bernoulli has no pdf, calculating max with derivatives is here not possible
    $endgroup$
    – Joey Doey
    Jan 25 at 14:52








  • 1




    $begingroup$
    Your likelihood formula is wrong - your formula doesn't depend on the data that you see, only $n$. When you use the correct formula you can differentiate the log likelihood to get the MLE.
    $endgroup$
    – Alex
    Jan 25 at 15:28










  • $begingroup$
    @Alex what do you mean?
    $endgroup$
    – Luke Marci
    Jan 25 at 15:31






  • 1




    $begingroup$
    The likelihood should depend on the data you see. E.g. suppose you just had $n = 1$ and observed $X_1 = x_1$. If that was a success ($x_1 = 1$) then the likelihood would be $theta$, and if it was a failure ($x_1 = 0$) then the likelihood would be $(1 - theta)$. In the first case the MLE would be $hat{theta} = 1$ and in the second case the MLE would be $hat{theta} = 0$.
    $endgroup$
    – Alex
    Jan 25 at 15:36










1




1




$begingroup$
bernoulli has no pdf, calculating max with derivatives is here not possible
$endgroup$
– Joey Doey
Jan 25 at 14:52






$begingroup$
bernoulli has no pdf, calculating max with derivatives is here not possible
$endgroup$
– Joey Doey
Jan 25 at 14:52






1




1




$begingroup$
Your likelihood formula is wrong - your formula doesn't depend on the data that you see, only $n$. When you use the correct formula you can differentiate the log likelihood to get the MLE.
$endgroup$
– Alex
Jan 25 at 15:28




$begingroup$
Your likelihood formula is wrong - your formula doesn't depend on the data that you see, only $n$. When you use the correct formula you can differentiate the log likelihood to get the MLE.
$endgroup$
– Alex
Jan 25 at 15:28












$begingroup$
@Alex what do you mean?
$endgroup$
– Luke Marci
Jan 25 at 15:31




$begingroup$
@Alex what do you mean?
$endgroup$
– Luke Marci
Jan 25 at 15:31




1




1




$begingroup$
The likelihood should depend on the data you see. E.g. suppose you just had $n = 1$ and observed $X_1 = x_1$. If that was a success ($x_1 = 1$) then the likelihood would be $theta$, and if it was a failure ($x_1 = 0$) then the likelihood would be $(1 - theta)$. In the first case the MLE would be $hat{theta} = 1$ and in the second case the MLE would be $hat{theta} = 0$.
$endgroup$
– Alex
Jan 25 at 15:36






$begingroup$
The likelihood should depend on the data you see. E.g. suppose you just had $n = 1$ and observed $X_1 = x_1$. If that was a success ($x_1 = 1$) then the likelihood would be $theta$, and if it was a failure ($x_1 = 0$) then the likelihood would be $(1 - theta)$. In the first case the MLE would be $hat{theta} = 1$ and in the second case the MLE would be $hat{theta} = 0$.
$endgroup$
– Alex
Jan 25 at 15:36












1 Answer
1






active

oldest

votes


















1












$begingroup$

The likelihood function for Bernoulli can be written as follows:
$$
L(theta)=begin{cases}theta, & X_1=1cr 1-theta, & X_1=0end{cases}times begin{cases}theta, & X_2=1cr 1-theta, & X_2=0end{cases}times cdotstimesbegin{cases}theta, & X_n=1cr 1-theta, & X_n=0end{cases}
$$

Note that $sum_{i=1}^n X_i=noverline X$ calculates the number of units in a sample, and $n-noverline X$ calculates the number of zeros. In the above product, $theta$ is multiplied as many times as there are units in the sample. And $1-theta$ is multiplied as many times as there are zeros in the sample. So
$$
L(theta) = theta^{noverline X}cdot (1-theta)^{n-noverline X}.
$$

Starting from here you can calculate MLE with derivatives.






share|cite|improve this answer









$endgroup$













    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    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%2f3087174%2fcompute-the-maximum-likelihood-estimator-for-%25ce%25b8%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












    $begingroup$

    The likelihood function for Bernoulli can be written as follows:
    $$
    L(theta)=begin{cases}theta, & X_1=1cr 1-theta, & X_1=0end{cases}times begin{cases}theta, & X_2=1cr 1-theta, & X_2=0end{cases}times cdotstimesbegin{cases}theta, & X_n=1cr 1-theta, & X_n=0end{cases}
    $$

    Note that $sum_{i=1}^n X_i=noverline X$ calculates the number of units in a sample, and $n-noverline X$ calculates the number of zeros. In the above product, $theta$ is multiplied as many times as there are units in the sample. And $1-theta$ is multiplied as many times as there are zeros in the sample. So
    $$
    L(theta) = theta^{noverline X}cdot (1-theta)^{n-noverline X}.
    $$

    Starting from here you can calculate MLE with derivatives.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      The likelihood function for Bernoulli can be written as follows:
      $$
      L(theta)=begin{cases}theta, & X_1=1cr 1-theta, & X_1=0end{cases}times begin{cases}theta, & X_2=1cr 1-theta, & X_2=0end{cases}times cdotstimesbegin{cases}theta, & X_n=1cr 1-theta, & X_n=0end{cases}
      $$

      Note that $sum_{i=1}^n X_i=noverline X$ calculates the number of units in a sample, and $n-noverline X$ calculates the number of zeros. In the above product, $theta$ is multiplied as many times as there are units in the sample. And $1-theta$ is multiplied as many times as there are zeros in the sample. So
      $$
      L(theta) = theta^{noverline X}cdot (1-theta)^{n-noverline X}.
      $$

      Starting from here you can calculate MLE with derivatives.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        The likelihood function for Bernoulli can be written as follows:
        $$
        L(theta)=begin{cases}theta, & X_1=1cr 1-theta, & X_1=0end{cases}times begin{cases}theta, & X_2=1cr 1-theta, & X_2=0end{cases}times cdotstimesbegin{cases}theta, & X_n=1cr 1-theta, & X_n=0end{cases}
        $$

        Note that $sum_{i=1}^n X_i=noverline X$ calculates the number of units in a sample, and $n-noverline X$ calculates the number of zeros. In the above product, $theta$ is multiplied as many times as there are units in the sample. And $1-theta$ is multiplied as many times as there are zeros in the sample. So
        $$
        L(theta) = theta^{noverline X}cdot (1-theta)^{n-noverline X}.
        $$

        Starting from here you can calculate MLE with derivatives.






        share|cite|improve this answer









        $endgroup$



        The likelihood function for Bernoulli can be written as follows:
        $$
        L(theta)=begin{cases}theta, & X_1=1cr 1-theta, & X_1=0end{cases}times begin{cases}theta, & X_2=1cr 1-theta, & X_2=0end{cases}times cdotstimesbegin{cases}theta, & X_n=1cr 1-theta, & X_n=0end{cases}
        $$

        Note that $sum_{i=1}^n X_i=noverline X$ calculates the number of units in a sample, and $n-noverline X$ calculates the number of zeros. In the above product, $theta$ is multiplied as many times as there are units in the sample. And $1-theta$ is multiplied as many times as there are zeros in the sample. So
        $$
        L(theta) = theta^{noverline X}cdot (1-theta)^{n-noverline X}.
        $$

        Starting from here you can calculate MLE with derivatives.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 26 at 3:47









        NChNCh

        6,8753825




        6,8753825






























            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%2f3087174%2fcompute-the-maximum-likelihood-estimator-for-%25ce%25b8%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

            Can a sorcerer learn a 5th-level spell early by creating spell slots using the Font of Magic feature?

            Does disintegrating a polymorphed enemy still kill it after the 2018 errata?

            A Topological Invariant for $pi_3(U(n))$