# Statistics Functions

## Introduction

This is the statistics extension. It contains few dozens of functions useful for statistical computations. It is a wrapper around 2 scientific libraries, namely DCDFLIB (Library of C routines for Cumulative Distributions Functions, Inverses, and Other parameters) by B. Brown & J. Lavato and RANDLIB by Barry Brown, James Lavato & Kathy Russell. Includes CD and PD functions.

## Installation

This » PECL extension is not bundled with PHP.

Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » http://pecl.php.net/package/stats.

The DLL for this PECL extension may be downloaded from either the » PHP Downloads page or from » http://pecl4win.php.net/

## Requirements

No external libraries are needed. The extension comes bundled with the libraries used.

## Table of Contents

- stats_absolute_deviation — Returns the absolute deviation of an array of values
- stats_cdf_beta — CDF function for BETA Distribution. Calculates any one parameter of the beta distribution given values for the others.
- stats_cdf_binomial — Calculates any one parameter of the binomial distribution given values for the others.
- stats_cdf_cauchy — Not documented
- stats_cdf_chisquare — Calculates any one parameter of the chi-square distribution given values for the others.
- stats_cdf_exponential — Not documented
- stats_cdf_f — Calculates any one parameter of the F distribution given values for the others.
- stats_cdf_gamma — Calculates any one parameter of the gamma distribution given values for the others.
- stats_cdf_laplace — Not documented
- stats_cdf_logistic — Not documented
- stats_cdf_negative_binomial — Calculates any one parameter of the negative binomial distribution given values for the others.
- stats_cdf_noncentral_chisquare — Calculates any one parameter of the non-central chi-square distribution given values for the others.
- stats_cdf_noncentral_f — Calculates any one parameter of the Non-central F distribution given values for the others.
- stats_cdf_poisson — Calculates any one parameter of the Poisson distribution given values for the others.
- stats_cdf_t — Calculates any one parameter of the T distribution given values for the others.
- stats_cdf_uniform — Not documented
- stats_cdf_weibull — Not documented
- stats_covariance — Computes the covariance of two data sets
- stats_den_uniform — Not documented
- stats_dens_beta — Not documented
- stats_dens_cauchy — Not documented
- stats_dens_chisquare — Not documented
- stats_dens_exponential — Not documented
- stats_dens_f — Description
- stats_dens_gamma — Not documented
- stats_dens_laplace — Not documented
- stats_dens_logistic — Not documented
- stats_dens_negative_binomial — Not documented
- stats_dens_normal — Not documented
- stats_dens_pmf_binomial — Not documented
- stats_dens_pmf_hypergeometric — Description
- stats_dens_pmf_poisson — Not documented
- stats_dens_t — Not documented
- stats_dens_weibull — Not documented
- stats_harmonic_mean — Returns the harmonic mean of an array of values
- stats_kurtosis — Computes the kurtosis of the data in the array
- stats_rand_gen_beta — Generates beta random deviate
- stats_rand_gen_chisquare — Generates random deviate from the distribution of a chisquare with "df" degrees of freedom random variable.
- stats_rand_gen_exponential — Generates a single random deviate from an exponential distribution with mean "av"
- stats_rand_gen_f — Generates a random deviate
- stats_rand_gen_funiform — Generates uniform float between low (exclusive) and high (exclusive)
- stats_rand_gen_gamma — Generates random deviates from a gamma distribution
- stats_rand_gen_ibinomial_negative — Generates a single random deviate from a negative binomial distribution. Arguments : n - the number of trials in the negative binomial distribution from which a random deviate is to be generated (n > 0), p - the probability of an event (0 < p < 1)).
- stats_rand_gen_ibinomial — Generates a single random deviate from a binomial distribution whose number of trials is "n" (n >= 0) and whose probability of an event in each trial is "pp" ([0;1]). Method : algorithm BTPE
- stats_rand_gen_int — Generates random integer between 1 and 2147483562
- stats_rand_gen_ipoisson — Generates a single random deviate from a Poisson distribution with mean "mu" (mu >= 0.0).
- stats_rand_gen_iuniform — Generates integer uniformly distributed between LOW (inclusive) and HIGH (inclusive)
- stats_rand_gen_noncenral_chisquare — Generates random deviate from the distribution of a noncentral chisquare with "df" degrees of freedom and noncentrality parameter "xnonc". d must be >= 1.0, xnonc must >= 0.0
- stats_rand_gen_noncentral_f — Generates a random deviate from the noncentral F (variance ratio) distribution with "dfn" degrees of freedom in the numerator, and "dfd" degrees of freedom in the denominator, and noncentrality parameter "xnonc". Method : directly generates ratio of noncentral numerator chisquare variate to central denominator chisquare variate.
- stats_rand_gen_noncentral_t — Generates a single random deviate from a noncentral T distribution
- stats_rand_gen_normal — Generates a single random deviate from a normal distribution with mean, av, and standard deviation, sd (sd >= 0). Method : Renames SNORM from TOMS as slightly modified by BWB to use RANF instead of SUNIF.
- stats_rand_gen_t — Generates a single random deviate from a T distribution
- stats_rand_get_seeds — Not documented
- stats_rand_phrase_to_seeds — generate two seeds for the RGN random number generator
- stats_rand_ranf — Returns a random floating point number from a uniform distribution over 0 - 1 (endpoints of this interval are not returned) using the current generator
- stats_rand_setall — Not documented
- stats_skew — Computes the skewness of the data in the array
- stats_standard_deviation — Returns the standard deviation
- stats_stat_binomial_coef — Not documented
- stats_stat_correlation — Not documented
- stats_stat_gennch — Not documented
- stats_stat_independent_t — Not documented
- stats_stat_innerproduct — Description
- stats_stat_noncentral_t — Calculates any one parameter of the noncentral t distribution give values for the others.
- stats_stat_paired_t — Not documented
- stats_stat_percentile — Not documented
- stats_stat_powersum — Not documented
- stats_variance — Returns the population variance