mina - 3 months ago 22

R Question

I am trying to replace NAs by truncated normal distribution values.

First I used

`sample`

`v.new <- replace(vector,v, sample(8,length(v),replace =FALSE))`

However when I try to use

`rtnorm`

`library(msm)`

# Some data

data("airquality")

airquality$Ozone

# My function

add.trunc.to.NAvector <- function(vector){

v <- NULL

for(i in 1:length(vector)){

if(is.na(vector[i])==TRUE)

v <- append(v, i)

}

mean.val <- mean(vector)

sd.val <- sd(vector)

min.val <- mean.val - 4 * sd.val

max.val <- mean.val + 4 * sd.val

v.new <- replace(vector,v, rtnorm(length(v), lower = min.val, upper = max.val))

return(v.new)

}

Answer

Should not this work?

```
v <- airquality$Ozone
v.new <- v
indices <- which(is.na(v))
m <- mean(v[-indices])
s <- sd(v[-indices])
v.new[indices] <- rtnorm(length(indices), lower = m-4*s, upper = m+4*s)
```