Plugin Design - Regressions


Description Attributes Coefficient Names Statistics See Also

Description

Draco includes a specialized class to aid in creating regression plugins.  The class, Plugin::RegressionPluginSkeleton, is meant to simplify the generation of results for regressions which conform to the simple regression attributes:
For example, the results would be applicable for oridinary least squares or probit MLE calculations.

Necessary Attributes

Regression plugins are expected to assign values to attributes during calculations for results generation.  The attributes are defined as follows:
Attribute Expected Type Description
@coef_names array of strings An array of strings that define the display names for each calculated coefficient (see below)
@covariance Matrix A matrix representing the covariance matrix resulting from the regression
@failure string or nil A string if the regression failed containing the reason, or nil otherwise
@statistics array of arrays An array of two-element arrays containing a statictic name and a value (see below)
@stderr Vector A vector representing the standard error of the coefficients
@tscores Vector A vector representing the t-scores for each coefficient
@x Vector A vector containing the estimates of the coefficients

Assigning Coefficient Names

Coefficient names can be automatically generated using a call to the generate_coef_names method.  The method accepts an array of strings, presumably independent variable names, and generates appropriate coefficient names.  The method also calls the method has_constant? to determine if a coefficient name of "Constant" should be included; the has_constant? method should be overridden appropriately to return a boolean.

Assigning Statistics

Statistics can be added to results via calls to the statistic method.  The method is used as follows:

statistic name, value

The name should be the plain text name of the statistic to display, and value should be a numeric result.

See Also

Plugin Design - Necessities
Plugin System Technical
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