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gausscov (version 0.1.9)

The Gaussian Covariate Method for Variable Selection

Description

Given the standard linear model the traditional way of deciding whether to include the jth covariate is to apply the F-test to decide whether the corresponding beta coefficient is zero. The Gaussian covariate method is completely different. The question as to whether the beta coefficient is or is not zero is replaced by the question as to whether the covariate is better or worse than i.i.d. Gaussian noise. The P-value for the covariate is the probability that Gaussian noise is better. Surprisingly this can be given exactly and it is the same a the P-value for the classical model based on the F-distribution. The Gaussian covariate P-value is model free, it is the same for any data set. Using the idea it is possible to do covariate selection for a small number of covariates 25 by considering all subsets. Post selection inference causes no problems as the P-values hold whatever the data. The idea extends to stepwise regression again with exact probabilities. In the simplest version the only parameter is a specified cut-off P-value which can be interpreted as the probability of a false positive being included in the final selection. For more information see the web site below and the accompanying papers: L. Davies and L. Duembgen, "Covariate Selection Based on a Model-free Approach to Linear Regression with Exact Probabilities", 2022, . L. Davies, "Linear Regression, Covariate Selection and the Failure of Modelling", 2022, .

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Version

Install

install.packages('gausscov')

Monthly Downloads

470

Version

0.1.9

License

GPL-3

Maintainer

Laurie Davies

Last Published

November 12th, 2022

Functions in gausscov (0.1.9)

fvauto

Vector autoregressive approximation
leukemia

Leukemia data
fr1st

Robust stepwise selection of covariates
fpval

Calculates the regression coefficients, the P-values and the standard P-values for the chosen subset ind
flag

Calculation of lagged covariates
fpsired

Calculates Hampel's redescending psi function
simgpval

Simulates Gaussian P-values
snspt

Sunspot data
fundr

Converts directed into an undirected graph
fselect

Selects the subsets specified by fasb.R and frasb.R.
redwine

Redwine data
mel-temp

Melbourne minimum temperature
f1st

Stepwise selection of covariates
decode

Decodes the number of a subset selected by fasb.R to give the covariates
fasb

Calculates all subsets where each included covariate is significant.
fgentrig

Generation of sine and cosine functions
fgeninter

Generation of interactions
f3st

Stepwise selection of covariates
abcq

American Business Cycle
f2st

Repeated stepwise selection of covariates
f3sti

Selection of covariates with given excluded covariates
frasb

Robust selection of covariates using Huber's psi-function or Hampel's redescending psi-function based on all subsets
frpval

Robust regression using Huber's psi-function or Hampel's three part redescending psi-function providing P-values
boston

Boston data
fgr1st

Calculates a dependence graph using Gaussian stepwise selection
fgr2st

Calculates an independence graph using repeated stepwise selection