CHANGELOG.md

Changelog

1.5.2 - 2026-05-13

• Adding kendallTau() method for Kendall tau-b rank correlation with tie handling
• Adding kendall method support to correlation()
• Adding chiSquaredTest() method for chi-squared goodness-of-fit tests
• Adding chiSquaredIndependence() method for chi-squared tests on contingency tables
• Adding fluent Statistics::chiSquaredTest() wrapper method

1.5.1 - 2026-05-12

• Adding rank() method for assigning 1-based ranks to data points, with support for average, min, max, dense, and ordinal tie strategies
• Adding percentileRank() method for calculating the percentile position of a value, with weak, strict, mean, and rank variants
• Adding fluent Statistics::rank() and Statistics::percentileRank() wrapper methods
• Fixing Statistics::tTestPaired() to preserve the original input order for paired observations
• Updating README documentation and examples for ranking and percentile-rank usage
• Improving Statistics test coverage for two-sample and paired t-test wrappers

1.5.0 - 2026-03-07

• Adding logarithmicRegression(), powerRegression(), and exponentialRegression() methods for non-linear regression models

1.4.0 - 2026-03-03

• Adding Utils\Arr class with extract() method for multi-column extraction from arrays of associative arrays, and partition() method for splitting arrays into matching/non-matching groups by field condition (supports ==, !=, >, <, >=, <= operators)
• Adding Utils\Format class with secondsToTime(), timeToSeconds(), secondsToHms(), and hmsToSeconds() methods for time formatting and parsing
• Adding Utils\Math class — reorganized from root namespace for consistency with Enums/ and Exception/ sub-directories
• Reorganized ArrUtil and Math into Utils\Arr and Utils\Math sub-namespace; original classes remain as deprecated proxies for backward compatibility
• Updated internal references in Stat, Freq, StreamingStat, and Statistics to use the new Utils namespace

1.3.1 - 2026-02-23

• Adding tTestTwoSample() method for two-sample independent t-test (Welch's t-test) — compares the means of two independent groups without assuming equal variances
• Adding tTestPaired() method for paired t-test — tests whether the mean difference between paired observations (e.g. before/after) is significantly different from zero
• Adding StudentT class for the Student's t-distribution (pdf, cdf, invCdf) — building block for t-tests and confidence intervals with small samples
• Adding tTest() method for one-sample t-test — like z-test but appropriate for small samples where the population standard deviation is unknown
• Adding zTest() method for one-sample Z-test — tests whether the sample mean differs significantly from a hypothesized population mean (includes p-value calculation)
• Adding Alternative enum (TwoSided, Greater, Less) for hypothesis testing
• Adding confidenceInterval() method for computing confidence intervals for the mean using the normal (z) distribution
• Adding rSquared() method for R² (coefficient of determination) — proportion of variance explained by linear regression

1.3.0 - 2026-02-22

• Adding StreamingStat class (experimental) for streaming/online computation of mean, variance, stdev, skewness, kurtosis, sum, min, and max with O(1) memory
• Adding percentile() method for computing the value at any percentile (0–100) with linear interpolation
• Adding coefficientOfVariation() method for relative dispersion (CV%), supporting both sample and population modes
• Adding trimmedMean() method for robust central tendency — computes the mean after removing outliers from each side
• Adding weightedMedian() method for computing the median with weighted observations
• Adding sem() method for standard error of the mean
• Adding meanAbsoluteDeviation() method for mean absolute deviation — average distance from the mean
• Adding medianAbsoluteDeviation() method for median absolute deviation — robust dispersion measure resistant to outliers
• Adding zscores() method for computing z-scores of each value in a dataset
• Adding outliers() method for z-score based outlier detection with configurable threshold
• Adding iqrOutliers() method for IQR-based outlier detection (box plot whiskers), robust for skewed data
• Adding rSquared() method for R² (coefficient of determination) — proportion of variance explained by linear regression

1.2.5 - 2026-02-22

• Adding kurtosis() method for excess kurtosis

1.2.4 - 2026-02-21

• Adding skewness() method for adjusted Fisher-Pearson sample skewness
• Adding pskewness() method for population (biased) skewness
• Full Coverage Tests (adding some edge cases)
• Create KDE example

1.2.3 - 2026-02-21

• Adding kde() method for Kernel Density Estimation — returns a closure that estimates PDF or CDF from sample data, supporting 9 kernel functions with aliases
• Adding kdeRandom() method for random sampling from a Kernel Density Estimate — returns a closure that generates random floats from the KDE distribution
• Introducing KdeKernel backed string enum — kde() and kdeRandom(). It accepts KdeKernel enum cases
• Adding Kernel Density Estimation (KDE) examples

1.2.2 - 2026-02-21

• Adding method parameter to quantiles() supporting 'exclusive' (default) and 'inclusive' interpolation methods
• Adding medianGrouped() method for estimating the median of grouped/binned continuous data using interpolation
• Adding Spearman rank correlation via method parameter in correlation() (method='ranked')
• Adding proportional linear regression via proportional parameter in linearRegression() for regression through the origin
• Adding optional pre-computed mean parameter to variance() (xbar) and pvariance() (mu)

1.2.1 - 2026-02-20

• Adding invCdf() method to normal distribution
• Adding getVariance() method to normal distribution (sigma squared)
• Adding getMedian() method to normal distribution (equals mean)
• Adding getMode() method to normal distribution (equals mean)
• Adding quantiles() method to normal distribution (divide into n equal-probability intervals)
• Adding overlap() method to normal distribution (overlapping coefficient between two distributions)
• Adding zscore() method to normal distribution (standard score)
• Adding samples() method to normal distribution (generate random samples with optional seed)
• Adding subtract() method to normal distribution (counterpart to add)
• Adding divide() method to normal distribution (counterpart to multiply)

1.2.0 - 2026-02-19

• Welcome to PHP 8.5
• Upgrading to PHPstan new rules (offsetAccess)
• Tests migrated from PestPHP 2 to PHPUnit 11
• Code Syntax checker from Pint to PHP CS Fixer

1.1.4 - 2025-04-25

• Adding fmean() method for computing the arithmetic mean with float numbers.

1.1.3 - 2024-12-14

• Adding multiply() method to scale NormalDist by a constant

1.1.2 - 2024-12-14

• Implementing add() method for NormalDist

1.1.1 - 2024-12-13

• Implementing fromSample method for NormalDist

1.1.0 - 2024-12-13

• Upgrading RectorPHP v 2
• Upgrading PHPStan v 2

1.0.2 - 2024-12-10

• NormalDist class, with cdf() and pdf()
• Fix deprecations for PHP 8.4

1.0.1 - 2024-11-21

• Welcome PHP 8.4
• Upgrading to Rector 1

1.0.0 - 2023-12-26

• Fixed median() function to handle unsorted data by @keatis
• Rector refactor
• PHPstan level 8
• Support for PHP 8.1 and above
• Add support for PHP 8.2 by @AmooAti
• Update to PestPHP v2 by @AmooAti
• Improving documentation (readme, contributing, code of conduct, security policies) by @AbhineshJha, @Arcturus22, @tvermaashutosh, @Abhishekgupta204, @Aryan4884
• Rector v0.18.5 by @sukuasoft
• Introducing Pint by @sukuasoft
• GitHub Actions: Updating actions/checkout v4

0.2.1 - 2022-02-22

• Linear regression

0.2.0 - 2022-02-21

• Raise Exception instead of returning null if there is no valid input. By Artem Trokhymchuk @trokhymchuk thanks for the PR #15;
• PHPStan, level 9

0.1.7 - 2022-02-19

• Code refactoring by @trokhymchuk
• Clean phpdoc blocks by @trokhymchuk
• Stat::correlation()
• PHPStan, level 8

0.1.6 -2022-02-17

• Stat::covariance()

0.1.5 - 2022-02-05

• frequencyTable()
• frequencyTableBySize()
• code refactoring and documenting some functions by Artem Trokhymchuk @trokhymchuk thanks for the PR #2
• add tests for Math class

0.1.4 - 2022-01-30

• quantiles()
• firstQuartile()
• thirdQuartile()

0.1.3 - 2022-01-29

• geometricMean(): geometric mean
• harmonicMean(): harmonic mean and weighted harmonic mean

0.1.2 - 2022-01-28

• pstdev(): Population standard deviation
• stdev(): Sample standard deviation
• pvariance(): variance for a population
• variance(): variance for a sample

0.1.1 - 2022-01-27

• Create Freq class with static method for managing frequencies table
• Create Stat class with static methods for basci statistic functions like: mean, mode, median, multimode...
• Refactor Statistics class in order to use logic provided by Freq and Stat class
• Create ArrUtil with some helpers/functions to manage arrays
• Add CICD test for PHP 8.1

Initial release - 2022-01-08

Initial release with:

• getMean()
• count()
• median()
• firstQuartile()
• thirdQuartile()
• mode()
• frequencies(): a frequency is the number of times a value of the data occurs;
• relativeFrequencies(): a relative frequency is the ratio (fraction or proportion) of the number of times a value of the data occurs in the set of all outcomes to the total number of outcomes;
• cumulativeFrequencies(): is the accumulation of the previous relative frequencies.;
• cumulativeRelativeFrequencies(): is the accumulation of the previous relative ratio.

0.1.0 - 2022-01-08

Initial release with:

• getMean()
• count()
• median()
• firstQuartile()
• thirdQuartile()
• mode()
• frequencies(): a frequency is the number of times a value of the data occurs;
• relativeFrequencies(): a relative frequency is the ratio (fraction or proportion) of the number of times a value of the data occurs in the set of all outcomes to the total number of outcomes;
• cumulativeFrequencies(): is the accumulation of the previous relative frequencies.;
• cumulativeRelativeFrequencies(): is the accumulation of the previous relative ratio.