README

A lightweight, well‑tested PHP library that delivers the most common descriptive‑statistics measures in a single, strictly‑typed class.


Package	`thesimon82/descriptive-statistics`
License	MIT
PHP	≥ 8.1
Namespace	`Renor\Statistics`
Main class	`DescriptiveStats`

📦 Installation

composer require thesimon82/descriptive-statistics

No extra extensions are needed—pure PHP 8.1+.

🚀 Quick‑start

<?php
declare(strict_types=1);

require 'vendor/autoload.php';

use Renor\Statistics\DescriptiveStats;

$data  = [2, 4, 4, 4, 5, 5, 7, 9];
$stats = new DescriptiveStats($data);

echo 'Mean (μ)             : ' . $stats->mean()                  . PHP_EOL; // 5
echo 'Median               : ' . $stats->median()                . PHP_EOL; // 4.5
echo 'Mode                 : ' . json_encode($stats->mode())     . PHP_EOL; // [4]
echo 'Var (population)     : ' . $stats->variance()              . PHP_EOL; // 4
echo 'St. dev (sample)     : ' . $stats->standardDeviation(true) . PHP_EOL; // 2.138…
echo 'IQR                  : ' . $stats->iqr()                   . PHP_EOL; // 2
echo 'MAD                  : ' . $stats->meanAbsoluteDeviation() . PHP_EOL; // 1.5
echo 'SEM                  : ' . $stats->standardError()         . PHP_EOL; // 0.756
echo '90th percentile      : ' . $stats->percentile(90)          . PHP_EOL; // 8.4
echo 'Min / Max            : ' . $stats->minValue() . ' / ' . $stats->maxValue() . PHP_EOL;

💡 API overview

Central tendency

Method	Description
`mean()`	Arithmetic mean
`median()`	50‑th percentile
`mode()`	Returns array – unimodal, multimodal or empty
`geometricMean()`	Requires all values > 0
`harmonicMean()`	Requires all values > 0
`trimmedMean($p)`	Trims p % at each tail (0 ≤ p < 50)

Dispersion

Method	Description
`range()`	Max − min
`variance($sample = false)`	Population or sample
`standardDeviation($sample = false)`	σ or s
`meanAbsoluteDeviation()`	MAD
`quartiles()`	`[Q1, Q2, Q3]` (Tukey hinges)
`iqr()`	Q3 − Q1

Uncertainty

Method	Description
`standardError()`	s / √n

Percentiles & extremes

Method	Description
`percentile($p)`	Linear interpolation, 0 ≤ p ≤ 100
`minValue()` / `maxValue()`	Dataset bounds

🧪 Running the tests

composer install          # if you haven't yet
vendor/bin/phpunit

The suite covers 100 % of the public API, including edge cases (single value, invalid parameters).

🤝 Contributing

Fork & create a feature branch
Follow PSR‑12 and keep everything strict_types=1
Add PHPUnit tests for any change
Open a pull request – discussions and improvements are welcome!

📄 License

Released under the MIT License

thesimon82 / descriptive-statistics

Maintainers

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