`dataFrame.columns.stat — phi()`

Description

The phi() method of the stat object computes the Phi coefficient between two selected binary columns.

Signature

dataFrame.columns(...columnNames).stat.phi()

Scope: columns
Family: stat
Returns: number

Argument

...columnNames ( string[] ): The name of the columns from which to compute the Phi coefficient.

Returns

coef (number): The computed Phi coefficient.

Notes

The method requires exactly two selected binary columns.
The Phi coefficient measures the association between two binary variables.
The coefficient ranges from -1 to 1.
Positive values indicate a positive association.
Negative values indicate a negative association.
A value close to 0 indicates little or no association.
The Phi coefficient is equivalent to the Pearson correlation coefficient computed on two binary variables.
The method is based on the 2 × 2 contingency table of the selected columns.

Example

// evaluate the Phi coefficient for 2 columns of the dataFrame
var coef = dataFrame.columns('groupA', 'groupB').stat.phi();

// log the stat details
notebook.log(coef);