Predict method for
Predict method for
# S3 method for lm_robust predict(object, newdata, se.fit = FALSE, interval = c("none", "confidence", "prediction"), alpha = 0.05, na.action = na.pass, pred.var = NULL, weights, ...)
an object of class 'lm_robust'
a data frame in which to look for variables with which to predict
logical. Whether standard errors are required, default = FALSE
type of interval calculation. Can be abbreviated, default = none
numeric denoting the test size for confidence intervals
function determining what should be done with missing values in newdata. The default is to predict NA.
the variance(s) for future observations to be assumed for prediction intervals.
variance weights for prediction. This can be a numeric vector or a bare (unquoted) name of the weights variable in the supplied newdata.
other arguments, unused
Produces predicted values, obtained by evaluating the regression
function in the frame
newdata for fits from
lm_lin. If the logical se.fit is TRUE, standard errors of the
predictions are calculated. Setting intervals specifies computation of
confidence or prediction (tolerance) intervals at the specified level,
sometimes referred to as narrow vs. wide intervals.
The equation used for the standard error of a prediction given a row of data \(x\) is: \(\sqrt(x \Sigma x')\),
where \(\Sigma\) is the estimated variance-covariance matrix from
The prediction intervals are for a single observation at each case in
newdata with error variance(s)
pred.var. The the default is to assume
that future observations have the same error variance as those used for
fitting, which is gotten from the fit
lm_robust object. If
weights is supplied, the inverse of this is used as a scale factor. If the
fit was weighted, the default is to assume constant prediction variance,
with a warning.
# Set seed set.seed(42) # Simulate data n <- 10 dat <- data.frame(y = rnorm(n), x = rnorm(n)) # Fit lm lm_out <- lm_robust(y ~ x, data = dat) # Get predicted fits fits <- predict(lm_out, newdata = dat) # With standard errors and confidence intervals fits <- predict(lm_out, newdata = dat, se.fit = TRUE, interval = "confidence") # Use new data as well new_dat <- data.frame(x = runif(n, 5, 8)) predict(lm_out, newdata = new_dat)#> 1 2 3 4 5 6 7 #> -0.6633382 -0.6957332 -0.4661705 -1.0056478 -0.6934163 -0.9964482 -0.9562101 #> 8 9 10 #> -0.8134173 -1.0041648 -0.8012341# You can also supply custom variance weights for prediction intervals new_dat$w <- runif(n) predict(lm_out, newdata = new_dat, weights = w, interval = "prediction")#> $fit #> fit lwr upr #> [1,] -0.6633382 -5.162176 3.835499 #> [2,] -0.6957332 -5.207346 3.815879 #> [3,] -0.4661705 -4.414089 3.481748 #> [4,] -1.0056478 -5.520872 3.509577 #> [5,] -0.6934163 -10.799452 9.412619 #> [6,] -0.9964482 -5.514685 3.521789 #> [7,] -0.9562101 -5.438922 3.526502 #> [8,] -0.8134173 -6.558348 4.931514 #> [9,] -1.0041648 -6.438104 4.429774 #> [10,] -0.8012341 -5.137823 3.535355 #>