org.apache.spark.ml.stat

Class ChiSquareTest

Object

org.apache.spark.ml.stat.ChiSquareTest

public class ChiSquareTest
extends Object

:: Experimental ::

Chi-square hypothesis testing for categorical data.

See Wikipedia for more information on the Chi-squared test.

Constructor Summary

Constructors

Constructor and Description
ChiSquareTest()

Method Summary

Modifier and Type	Method and Description
static Dataset<Row>	test(Dataset<Row> dataset, String featuresCol, String labelCol) Conduct Pearson's independence test for every feature against the label.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ChiSquareTest

public ChiSquareTest()

Method Detail

test

public static Dataset<Row> test(Dataset<Row> dataset,
                                String featuresCol,
                                String labelCol)

Conduct Pearson's independence test for every feature against the label. For each feature, the (feature, label) pairs are converted into a contingency matrix for which the Chi-squared statistic is computed. All label and feature values must be categorical.

The null hypothesis is that the occurrence of the outcomes is statistically independent.

Parameters:

dataset - DataFrame of categorical labels and categorical features. Real-valued features will be treated as categorical for each distinct value.

featuresCol - Name of features column in dataset, of type Vector (VectorUDT)

labelCol - Name of label column in dataset, of any numerical type

Returns:

DataFrame containing the test result for every feature against the label. This DataFrame will contain a single Row with the following fields: - pValues: Vector - degreesOfFreedom: Array[Int] - statistics: Vector Each of these fields has one value per feature.