HuasoFoundries /
math_histogram
| @@ 798-821 (lines=24) @@ | ||
| 795 | * @see stDev() |
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| 796 | * @see calc() |
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| 797 | */ |
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| 798 | public function skewness() |
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| 799 | { |
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| 800 | if (!array_key_exists('skewness', $this->_calculatedValues)) { |
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| 801 | try { |
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| 802 | $count = $this->count(); |
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| 803 | try { |
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| 804 | $stDev = $this->stDev(); |
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| 805 | try { |
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| 806 | $sumdiff3 = $this->__sumdiff(3); |
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| 807 | } catch (\PEAR_Exception $e) { |
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| 808 | return $sumdiff3; |
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| 809 | } |
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| 810 | } catch (\PEAR_Exception $e) { |
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| 811 | return $stDev; |
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| 812 | } |
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| 813 | } catch (\PEAR_Exception $e) { |
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| 814 | return $count; |
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| 815 | } |
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| 816 | ||
| 817 | $this->_calculatedValues['skewness'] = ($sumdiff3 / ($count * pow($stDev, 3))); |
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| 818 | } |
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| 819 | return $this->_calculatedValues['skewness']; |
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| 820 | } |
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| 821 | ||
| 822 | /** |
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| 823 | * Calculates the kurtosis of the data distribution in the set |
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| 824 | * The kurtosis measures the degrees of peakedness of a distribution. |
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| @@ 840-864 (lines=25) @@ | ||
| 837 | * @see stDev() |
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| 838 | * @see calc() |
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| 839 | */ |
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| 840 | public function kurtosis() |
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| 841 | { |
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| 842 | if (!array_key_exists('kurtosis', $this->_calculatedValues)) { |
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| 843 | try { |
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| 844 | $count = $this->count(); |
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| 845 | try { |
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| 846 | $stDev = $this->stDev(); |
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| 847 | try { |
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| 848 | $sumdiff4 = $this->__sumdiff(4); |
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| 849 | } catch (\PEAR_Exception $e) { |
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| 850 | return $sumdiff4; |
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| 851 | } |
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| 852 | } catch (\PEAR_Exception $e) { |
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| 853 | return $stDev; |
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| 854 | } |
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| 855 | } catch (\PEAR_Exception $e) { |
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| 856 | return $count; |
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| 857 | } |
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| 858 | ||
| 859 | $this->_calculatedValues['kurtosis'] = ($sumdiff4 / ($count * pow($stDev, 4))) - 3; |
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| 860 | } |
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| 861 | return $this->_calculatedValues['kurtosis']; |
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| 862 | } |
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| 863 | ||
| 864 | /** |
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| 865 | * Calculates the median of a data set. |
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| 866 | * The median is the value such that half of the points are below it |
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| 867 | * in a sorted data set. |
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