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Topic

Error in standard deviation calculation

Page d'accueil ' Communauté ' Généralités ' Erreur dans le calcul de l'écart-type

Voir les messages de 4 - 1 à 4 (sur un total de 4)
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  • #34103
    Norbert Bakkers
    Participant

    When converting a standard deviation calculation (from the statistics menu) into a formula I noticed the following:
    The first part of the formula consists of ‘SQRT(n/(n-1))’, should this not be ‘SQRT(1/(n-1))’?

    #34106
    Norbert Bakkers
    Participant

    When converting a standard deviation calculation (from the statistics menu) into a formula I noticed the following:
    The first part of the formula consists of ‘SQRT(n/(n-1))’, should this not be ‘SQRT(1/(n-1))’?

    #34104
    Bernhard Kantz
    Participant

    The formula is correct. The standard deviation can be written in to forms. One uses a factor 1/(n-1) and the other one a factor n/(n-1). If you convert the first formula into the second formula, you make use of the equation Sum(X) = n * Mean(X). This is where the factor n comes in.

    #34105
    Norbert Bakkers
    Participant

    Thank you for the explanation, it makes perfect sense now. I also made a formula using the standard deviation equation I know and they did indeed give identical results

Voir les messages de 4 - 1 à 4 (sur un total de 4)
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