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SAP HANA Predictive Analysis Library (PAL)

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3.7.9 Univariate Statistics<br />

This function calculates several basic univariate statistics including mean, median, variance, standard<br />

deviation, skewness and kurtosis. The function treats each column as one dataset and calculates the statistics<br />

respectively.<br />

Mean<br />

where X i is the i-th element of the dataset and n is the size of the dataset.<br />

Median<br />

The median is defined as the numerical value separating the higher half of a dataset from the lower half. If<br />

there is an even number of observations, the median is defined to be the mean of the two middle elements.<br />

Lower Quartile and Upper Quartile<br />

Use the median to divide the elements of the dataset into two halves. Do not include the median in either half.<br />

The lower quartile value is the median of the lower half of the data. The upper quartile value is the median of<br />

the upper half of the data.<br />

Variance (population)<br />

where n is the size of the dataset and is the mean of x.<br />

Variance (sample)<br />

where n is the size of the dataset and is the mean of x.<br />

Standard Deviation (population)<br />

Standard Deviation (sample)<br />

Skewness<br />

Skewness is a measure of the degree of asymmetry. Suppose that<br />

532 P U B L I C<br />

<strong>SAP</strong> <strong>HANA</strong> <strong>Predictive</strong> <strong>Analysis</strong> <strong>Library</strong> (<strong>PAL</strong>)<br />

<strong>PAL</strong> Functions

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