Confidence intervals for autocorrelation function

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Given a time series data sample I have computed autocorrelation coefficients for various lags, the result looks something like this



enter image description here



How do I compute the confidence intervals around the sample autocorrelation curve?



The reason for that is to see if another autocorrelation curve computed from samples generated by some model is within those confidence intervals.










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  • Maybe try with a bootstrap method.
    – user2974951
    7 hours ago










  • @user2974951 thanks for your suggestion, I will try that. However, I was hoping to find out if some asymptotic approximation formula was available.
    – Anya
    6 hours ago
















up vote
2
down vote

favorite
1












Given a time series data sample I have computed autocorrelation coefficients for various lags, the result looks something like this



enter image description here



How do I compute the confidence intervals around the sample autocorrelation curve?



The reason for that is to see if another autocorrelation curve computed from samples generated by some model is within those confidence intervals.










share|cite|improve this question







New contributor




Anya is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.



















  • Maybe try with a bootstrap method.
    – user2974951
    7 hours ago










  • @user2974951 thanks for your suggestion, I will try that. However, I was hoping to find out if some asymptotic approximation formula was available.
    – Anya
    6 hours ago












up vote
2
down vote

favorite
1









up vote
2
down vote

favorite
1






1





Given a time series data sample I have computed autocorrelation coefficients for various lags, the result looks something like this



enter image description here



How do I compute the confidence intervals around the sample autocorrelation curve?



The reason for that is to see if another autocorrelation curve computed from samples generated by some model is within those confidence intervals.










share|cite|improve this question







New contributor




Anya is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











Given a time series data sample I have computed autocorrelation coefficients for various lags, the result looks something like this



enter image description here



How do I compute the confidence intervals around the sample autocorrelation curve?



The reason for that is to see if another autocorrelation curve computed from samples generated by some model is within those confidence intervals.







confidence-interval autocorrelation






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asked 7 hours ago









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  • Maybe try with a bootstrap method.
    – user2974951
    7 hours ago










  • @user2974951 thanks for your suggestion, I will try that. However, I was hoping to find out if some asymptotic approximation formula was available.
    – Anya
    6 hours ago
















  • Maybe try with a bootstrap method.
    – user2974951
    7 hours ago










  • @user2974951 thanks for your suggestion, I will try that. However, I was hoping to find out if some asymptotic approximation formula was available.
    – Anya
    6 hours ago















Maybe try with a bootstrap method.
– user2974951
7 hours ago




Maybe try with a bootstrap method.
– user2974951
7 hours ago












@user2974951 thanks for your suggestion, I will try that. However, I was hoping to find out if some asymptotic approximation formula was available.
– Anya
6 hours ago




@user2974951 thanks for your suggestion, I will try that. However, I was hoping to find out if some asymptotic approximation formula was available.
– Anya
6 hours ago










2 Answers
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A quick google search with "confidence intervals for acfs" yielded



Janet M. Box-Steffensmeier, John R. Freeman, Matthew P. Hitt, Jon C. W. Pevehouse: Time Series Analysis for the Social Sciences.



In there, on page 38, the standard error of an AC estimator at lag k is stated to be



$AC_SE,k = sqrtN^-1left(1+2sum_i=1^k[AC_i^2] right)$



where $AC_i$ is the AC esimate at lag i and N is the number of time steps in your sample. This is assuming that the true underlying process is actually MA. Assuming asympotic normality of the AC estimator, you can calculate the confidence intervals at each lag then as



$CI_AC_k = [AC_k - 1.96timesdfracAC_SE,ksqrtN, AC_k + 1.96timesdfracAC_SE,ksqrtN]$.



For some further info, see also this and this.






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    up vote
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    When the ACF is estimated from data I think also the error should be directly computed from the same data. I think that is generally the safest and most conservative approach. I would just store the resulting products of the signal with itself after each shift in the row of a matrix. Then you have the full distribution of values at each shift. Computing the column-wise average and the std/sem gives you a estimate of the AC and its variation. Bootstrapping and other resampling procedures on that matrix enable you to estimate the confidence intervals. This has the advantage that there are no special assumptions to be made and it can always be made compatible with your specific AC computation (normalization, padding etc.).






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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      2
      down vote



      accepted










      A quick google search with "confidence intervals for acfs" yielded



      Janet M. Box-Steffensmeier, John R. Freeman, Matthew P. Hitt, Jon C. W. Pevehouse: Time Series Analysis for the Social Sciences.



      In there, on page 38, the standard error of an AC estimator at lag k is stated to be



      $AC_SE,k = sqrtN^-1left(1+2sum_i=1^k[AC_i^2] right)$



      where $AC_i$ is the AC esimate at lag i and N is the number of time steps in your sample. This is assuming that the true underlying process is actually MA. Assuming asympotic normality of the AC estimator, you can calculate the confidence intervals at each lag then as



      $CI_AC_k = [AC_k - 1.96timesdfracAC_SE,ksqrtN, AC_k + 1.96timesdfracAC_SE,ksqrtN]$.



      For some further info, see also this and this.






      share|cite|improve this answer








      New contributor




      samtt is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.





















        up vote
        2
        down vote



        accepted










        A quick google search with "confidence intervals for acfs" yielded



        Janet M. Box-Steffensmeier, John R. Freeman, Matthew P. Hitt, Jon C. W. Pevehouse: Time Series Analysis for the Social Sciences.



        In there, on page 38, the standard error of an AC estimator at lag k is stated to be



        $AC_SE,k = sqrtN^-1left(1+2sum_i=1^k[AC_i^2] right)$



        where $AC_i$ is the AC esimate at lag i and N is the number of time steps in your sample. This is assuming that the true underlying process is actually MA. Assuming asympotic normality of the AC estimator, you can calculate the confidence intervals at each lag then as



        $CI_AC_k = [AC_k - 1.96timesdfracAC_SE,ksqrtN, AC_k + 1.96timesdfracAC_SE,ksqrtN]$.



        For some further info, see also this and this.






        share|cite|improve this answer








        New contributor




        samtt is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.



















          up vote
          2
          down vote



          accepted







          up vote
          2
          down vote



          accepted






          A quick google search with "confidence intervals for acfs" yielded



          Janet M. Box-Steffensmeier, John R. Freeman, Matthew P. Hitt, Jon C. W. Pevehouse: Time Series Analysis for the Social Sciences.



          In there, on page 38, the standard error of an AC estimator at lag k is stated to be



          $AC_SE,k = sqrtN^-1left(1+2sum_i=1^k[AC_i^2] right)$



          where $AC_i$ is the AC esimate at lag i and N is the number of time steps in your sample. This is assuming that the true underlying process is actually MA. Assuming asympotic normality of the AC estimator, you can calculate the confidence intervals at each lag then as



          $CI_AC_k = [AC_k - 1.96timesdfracAC_SE,ksqrtN, AC_k + 1.96timesdfracAC_SE,ksqrtN]$.



          For some further info, see also this and this.






          share|cite|improve this answer








          New contributor




          samtt is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
          Check out our Code of Conduct.









          A quick google search with "confidence intervals for acfs" yielded



          Janet M. Box-Steffensmeier, John R. Freeman, Matthew P. Hitt, Jon C. W. Pevehouse: Time Series Analysis for the Social Sciences.



          In there, on page 38, the standard error of an AC estimator at lag k is stated to be



          $AC_SE,k = sqrtN^-1left(1+2sum_i=1^k[AC_i^2] right)$



          where $AC_i$ is the AC esimate at lag i and N is the number of time steps in your sample. This is assuming that the true underlying process is actually MA. Assuming asympotic normality of the AC estimator, you can calculate the confidence intervals at each lag then as



          $CI_AC_k = [AC_k - 1.96timesdfracAC_SE,ksqrtN, AC_k + 1.96timesdfracAC_SE,ksqrtN]$.



          For some further info, see also this and this.







          share|cite|improve this answer








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          answered 4 hours ago









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              up vote
              1
              down vote













              When the ACF is estimated from data I think also the error should be directly computed from the same data. I think that is generally the safest and most conservative approach. I would just store the resulting products of the signal with itself after each shift in the row of a matrix. Then you have the full distribution of values at each shift. Computing the column-wise average and the std/sem gives you a estimate of the AC and its variation. Bootstrapping and other resampling procedures on that matrix enable you to estimate the confidence intervals. This has the advantage that there are no special assumptions to be made and it can always be made compatible with your specific AC computation (normalization, padding etc.).






              share|cite|improve this answer
























                up vote
                1
                down vote













                When the ACF is estimated from data I think also the error should be directly computed from the same data. I think that is generally the safest and most conservative approach. I would just store the resulting products of the signal with itself after each shift in the row of a matrix. Then you have the full distribution of values at each shift. Computing the column-wise average and the std/sem gives you a estimate of the AC and its variation. Bootstrapping and other resampling procedures on that matrix enable you to estimate the confidence intervals. This has the advantage that there are no special assumptions to be made and it can always be made compatible with your specific AC computation (normalization, padding etc.).






                share|cite|improve this answer






















                  up vote
                  1
                  down vote










                  up vote
                  1
                  down vote









                  When the ACF is estimated from data I think also the error should be directly computed from the same data. I think that is generally the safest and most conservative approach. I would just store the resulting products of the signal with itself after each shift in the row of a matrix. Then you have the full distribution of values at each shift. Computing the column-wise average and the std/sem gives you a estimate of the AC and its variation. Bootstrapping and other resampling procedures on that matrix enable you to estimate the confidence intervals. This has the advantage that there are no special assumptions to be made and it can always be made compatible with your specific AC computation (normalization, padding etc.).






                  share|cite|improve this answer












                  When the ACF is estimated from data I think also the error should be directly computed from the same data. I think that is generally the safest and most conservative approach. I would just store the resulting products of the signal with itself after each shift in the row of a matrix. Then you have the full distribution of values at each shift. Computing the column-wise average and the std/sem gives you a estimate of the AC and its variation. Bootstrapping and other resampling procedures on that matrix enable you to estimate the confidence intervals. This has the advantage that there are no special assumptions to be made and it can always be made compatible with your specific AC computation (normalization, padding etc.).







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered 1 hour ago









                  Jojo

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