New Functions in Week 10

nobs

{gdata}

Compute the number of non-missing observations

resid

{stats}

Extracts model residuals from objects returned by modeling functions

vif

{car}

Calculate Variance Inflation Factor

pchisq

{stats}

Gives the distribution function of the chi-squared distribution

sample_frac

{dplyr}

Sample a fraction of observations from a data frame

vcovHC

{sandwich}

Heteroscedasticity-consistent estimation of the covariance matrix of the coefficient estimates

coeftest

{lmtest}

Inference for Estimated Coefficients

bptest

{lmtest}

Breusch-Pagan Test for Homoscedasticity

The end!