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    @stdlib/stats-anova1
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    0.0.7 • Public • Published

    One Way ANOVA

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    Perform a one-way analysis of variance.

    Installation

    npm install @stdlib/stats-anova1

    Usage

    var anova1 = require( '@stdlib/stats-anova1' );

    anova1( x, factor[, opts] )

    For an array or typed array of numeric values x and an array of classifications factor, a one-way analysis of variance is performed. The hypotheses are given as follows:

    Hypotheses of ANOVA

    The function returns an object containing the treatment and error squared errors, degrees of freedom, mean squared errors, and both the p-value and F score.

    var out;
    var x;
    var y;
    
    x = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
    y = [ 'Treatment A', 'Treatment B', 'Treatment C', 'Control', 'Treatment A', 'Treatment B', 'Treatment C', 'Control', 'Treatment A', 'Treatment B', 'Treatment C', 'Control' ];
    
    out = anova1( x, y );
    /* returns
        {
            'treatment': { 'df': 11, 'ss': 15, 'ms': 5 },
            'error': { 'df': 8, 'ss': 128, 'ms': 16 },
            'statistic': 0.3125,
            'pValue': 0.81607947904798,
            'means':
              { 'Treatment A': { 'mean': 5, 'sampleSize': 3, 'SD': 4 },
                'Treatment B': { 'mean': 6, 'sampleSize': 3, 'SD': 4 },
                'Treatment C': { 'mean': 7, 'sampleSize': 3, 'SD': 4 },
                'Control': { 'mean': 8, 'sampleSize': 3, 'SD': 4 } },
            'method': 'One-Way ANOVA'
        }
    */

    The returned object comes with a .print() method which when invoked will print a formatted output of the results of the hypothesis test. print accepts a digits option that controls the number of decimal digits displayed for the outputs and a decision option, which when set to false will hide the test decision.

    var out;
    var x;
    var y;
    
    x = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
    y = [ 'Treatment A', 'Treatment B', 'Treatment C', 'Control', 'Treatment A', 'Treatment B', 'Treatment C', 'Control', 'Treatment A', 'Treatment B', 'Treatment C', 'Control' ];
    
    out = anova1( x, y );
    console.log( out.print() );
    /* =>
        One-Way ANOVA
    
        Null Hypothesis: All Means Equal
        Alternate Hypothesis: At Least one Mean not Equal
    
                      df   SS     MS    F Score   P Value
        Treatment     3    15     5     0.3125    0.8161
        Errors        8    128    16
    
        Fail to Reject Null: 0.8161 >= 0.05
    */

    The function accepts the following options:

    • alpha: number in the interval [0,1] giving the significance level of the hypothesis test. Default: 0.05.
    • decision: a boolean value indicating if function is to return a decision of either rejection of the null hypothesis or failure to reject the null hypothesis. Default: false

    By default, the test is carried out at a significance level of 0.05. To choose a custom significance level, set the alpha option.

    var x = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
    var y = [ 'Treatment A', 'Treatment B', 'Treatment C', 'Control', 'Treatment A', 'Treatment B', 'Treatment C', 'Control', 'Treatment A', 'Treatment B', 'Treatment C', 'Control' ];
    
    var out = anova1( x, y );
    var table = out.print();
    /* e.g., returns
        One-Way ANOVA
    
        Null Hypothesis: All Means Equal
        Alternate Hypothesis: At Least one Mean not Equal
    
                      df   SS     MS    F Score   P Value
        Treatment     3    15     5     0.3125    0.8161
        Errors        8    128    16
    
        Fail to Reject Null: 0.8161 >= 0.05
    */
    
    out = anova1( x, y, {
        'alpha': 0.9
    });
    table = out.print();
    /* e.g., returns
        One-Way ANOVA
    
        Null Hypothesis: All Means Equal
        Alternate Hypothesis: At Least one Mean not Equal
    
                      df   SS     MS    F Score   P Value
        Treatment     3    15     5     0.3125    0.8161
        Errors        8    128    16
    
        Reject Null: 0.8161 <= 0.9
    */

    Notes

    Examples

    var anova1 = require( '@stdlib/stats-anova1' );
    
    var x = [ 3, 4, 5, 6, 2, 5, 10, 12, 8, 10 ];
    var f = [ 'control', 'treatA', 'treatB', 'control', 'treatA', 'treatB', 'control', 'treatA', 'treatB', 'control' ];
    
    var out = anova1( x, f, {
        'decision': true
    });
    
    console.log( out.print() );
    
    out = anova1( x, f, {
        'alpha': 0.9
    });
    
    console.log( out.print() );

    Notice

    This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

    For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/stats-anova1

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    79

    Version

    0.0.7

    License

    Apache-2.0

    Unpacked Size

    77.7 kB

    Total Files

    16

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    • stdlib-bot
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