select
{dplyr}
Select columns from a tibble/data frame
sample_frac
{dplyr}
Sample a fraction of observations from a data frame
pchisq
{stats}
Gives the distribution function of the chi-squared distribution
nobs
{gdata}
Compute the number of non-missing observations
coeftest
{lmtest}
Inference for Estimated Coefficients
set.seed
{base}
Initialise a pseudorandom number generator.
filter
{dplyr}
Filter out rows of a data frame according to logical vector
resid
{stats}
Extracts model residuals from objects returned by modeling functions
vif
{car}
Calculate Variance Inflation Factor
bptest
{lmtest}
Breusch-Pagan Test for Homoscedasticity
vcovHC
{sandwich}
Heteroscedasticity-consistent estimation of the covariance matrix of the coefficient estimates
The end!