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    Rootogram

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    Aryyaas A
    Rootograms are a graphical tool introduced by John Tukey in 1971 to visualize how closely a data set follows a normal distribution. It uses the square root of frequencies rather than actual frequencies to better show deviations in the tails of a distribution. Rootograms have been used to analyze issues like overdispersion and excess zeros in count data regression models. There are three types of rootograms - standing, hanging, and suspended - that show the relationship between observed and expected frequencies in different ways.

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    Rootogram

    Uploaded by

    Aryyaas A
    92 views9 pages
    Rootograms are a graphical tool introduced by John Tukey in 1971 to visualize how closely a data set follows a normal distribution. It uses the square root of frequencies rather than actual frequencies to better show deviations in the tails of a distribution. Rootograms have been used to analyze issues like overdispersion and excess zeros in count data regression models. There are three types of rootograms - standing, hanging, and suspended - that show the relationship between observed and expected frequencies in different ways.

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    Rootograms are a graphical tool introduced by John Tukey in 1971 to visualize how closely a data set follows a normal distribution. It uses the square root of frequencies rather than actual frequencies to better show deviations in the tails of a distribution. Rootograms have been used to analyze issues like overdispersion and excess zeros in count data regression models. There are three types of rootograms - standing, hanging, and suspended - that show the relationship between observed and expected frequencies in different ways.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    92 views9 pages

    Rootogram

    Uploaded by

    Aryyaas A
    Rootograms are a graphical tool introduced by John Tukey in 1971 to visualize how closely a data set follows a normal distribution. It uses the square root of frequencies rather than actual frequencies to better show deviations in the tails of a distribution. Rootograms have been used to analyze issues like overdispersion and excess zeros in count data regression models. There are three types of rootograms - standing, hanging, and suspended - that show the relationship between observed and expected frequencies in different ways.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 9

    WHAT ARE THE ADVANTAGES

    OF WORKING WITH A

    ROOTOGRAM?

    www.benchmarksixsigma.com
    MEANING

    Rootogram is a graphical tool


    introduced by John Tukey in 1971
    that is used to visualize how closely
    a data set follows a normal
    distribution. It uses the square root
    of the frequencies (or the residuals)
    rather than actual frequencies, as in
    a histogram. This enables easy
    visualization of the deviations in the
    tails.

    www.benchmarksixsigma.com
    A rootogram is a visual tool that
    Tukey initially used to assess the
    goodness of fit of univariate
    distributions. Christian Kleiber of the
    Universitat Basel and Achim Zeileis
    of the Universitat Innsbruck, in their
    paper “Visualizing Count Data
    Regressions Using Rootograms”, have
    used rootograms to look at issues
    such as overdispersion, excess zeros
    in regression models for count data.

    www.benchmarksixsigma.com
    Count data regression plots are
    done in bar plots of the expected
    and observed frequencies.
    Rootograms are used to see both
    continuous and count data fit.

    www.benchmarksixsigma.com

    Rootograms compare the


    observed frequencies using bars
    (histograms) and the expected
    frequencies using a curve on a
    square root scale. Taking the
    square root scale transforms the
    date to adjust to the scale
    differences across the intervals.

    www.benchmarksixsigma.com
    This makes the deviations across
    the interval for more minor
    observed/expected frequencies
    more visible in the plot. For
    example, the deviations of 9 as
    comped to 3600 would only be
    1:400. However, the square of the
    numbers 3 and 60 is 1:20. This is a
    visual magnification of 20 times.

    www.benchmarksixsigma.com
    There are three types of
    rootograms. The standing
    rootograms show the bars and a
    curve. In this, the deviations are
    not aligned. The standing
    rootogram is the least used as it
    plots the bars and the curve
    representing the model. However,
    the fit is not shown. The hanging
    rootograms align all the deviations
    along the horizontal axis.

    www.benchmarksixsigma.com
    The bars hang from the curve
    representing the expected
    frequencies, whereas the
    suspended rootogram mainly
    shows deviations against the
    observed frequencies. The hanging
    and suspended use the horizontal
    reference line, which shows the
    deviations between the observed
    and expected frequencies.

    www.benchmarksixsigma.com
    INQUIRE NOW!

    Learn about Rootogram in our


    Lean Six Sigma programs

    +91 98113 70943

    www.benchmarksixsigma.com

    https://tinyurl.com/BSSinquire

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