On 3/21/20 9:35 AM, varin sacha via R-help wrote:
Dear R-experts,
Here below my R code giving an error message that I don't understand. If
somebody can help me to fix it, it would be highly appreciated.
# # # # # # # # # # # # # # # # # # # # # # # #
install.packages( "robustbase",dependencies=TRUE )
install.packages( "boot",dependencies=TRUE )
library(boot)
library(robustbase)
n<-500
b<-runif(n, 0, 5)
z <- rnorm(n, 2, 3)
a <- runif(n, 0, 5)
df<-data.frame(b,z,a)
y_model<- 0.1*b - 0.5 * z - a + 10
y_obs <- y_model +c( rnorm(n*0.9, 0, 0.1), rnorm(n*0.1, 0, 0.5) )
Two errors: First, you need to have the y_obs vector in the df dataframe
if you later reference it as a column.
# function to obtain MSE
MSE <- function(data, indices, formula) {
d <- data[indices, ] # allows boot to select sample
fit <- lmrob(formula, data = d)
ypred <- predict(fit)
mean((d[["y_obs "]] - ypred)^2)
The second error is the misspelling . Remove the space
}
# Make the results reproducible
set.seed(1234)
# bootstrapping with 500 replications
results <- boot(data = df, statistic = MSE,
R = 500, formula = y_obs ~ b+z+a)
boot.ci(results, type="bca")
Now get:
> boot.ci(results, type="bca")
BOOTSTRAP CONFIDENCE INTERVAL CALCULATIONS
Based on 500 bootstrap replicates
CALL :
boot.ci(boot.out = results, type = "bca")
Intervals :
Level BCa
95% ( 0.0237, 0.0460 )
Calculations and Intervals on Original Scale
Some BCa intervals may be unstable
--
David.
# # # # # # # # # # # # # # # # # # # # # # # # #
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______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
