stats_kurtosis
(PECL stats >= 1.0.0)
stats_kurtosis — Computes the kurtosis of the data in the array
パラメータ
a-
The input array
戻り値
Returns the kurtosis of the values in a,
or false if a is empty or is not an array.
＋add a note
User Contributed Notes 1 note
Angel J. Salinas ¶
9 years ago
// If you don't have the php_stats library, you can use this function:
public static function getKurtosis( $values )
{
$numValues = count( $values );
if ( $numValues == 0 ) {
return 0.0;
}
// Use function from php_stats library if available
if ( function_exists( 'stats_kurtosis' ) ) {
return stats_kurtosis( $values );
}
$mean = array_sum( $values ) / floatval( $numValues );
$add2 = 0.0;
$add4 = 0.0;
foreach ( $values as $value ) {
if ( ! is_numeric( $value ) ) {
return false;
}
$dif = $value - $mean;
$dif2 = $dif * $dif;
$add2 += $dif2;
$add4 += ( $dif2 * $dif2 );
} // foreach values
$variance = $add2 / floatval( $numValues );
return ( $add4 * $numValues ) / ( $add2 * $add2 ) - 3.0;
}
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