View source: R/rms_SandwichAddon.R
robcov_alt | R Documentation |
This is an alternative to the 'rms'-package robust covariance
matrix that uses the 'sandwich' package vcovHC()
function
instead of the 'rms'-built-in estimator. The advantage being that
many more estimation types are available.
robcov_alt(fit, type = "HC3", ...)
fit |
The ols fit that |
type |
a character string specifying the estimation type. See
|
... |
You should specify type= followed by some of the alternative available
for the |
model The fitted model with adjusted variance and df.residual set to NULL
# Generate some data n <- 500 x1 <- runif(n) * 2 x2 <- runif(n) y <- x1^3 + x2 + rnorm(n) library(rms) library(sandwich) dd <- datadist(x1, x2, y) org.op <- options(datadist = "dd") # Main function f <- ols(y ~ rcs(x1, 3) + x2) # Check the bread bread(f) # Check the HC-matrix vcovHC(f, type = "HC4m") # Adjust the model so that it uses the HC4m variance f_rob <- robcov_alt(f, type = "HC4m") # Get the new HC4m-matrix # - this function just returns the f_rob$var matrix vcov(f_rob) # Now check the confidence interval for the function confint(f_rob) options(org.op)
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