It depends on the na.action used in lm(), which defaults to na.omit. Here's an example:
x <- c(1:5, NA, 7:10) y <- rnorm(x) fitted(lm(y ~ x))
1 2 3 4 5 7
8
0.68680104 0.47913875 0.27147646 0.06381417 -0.14384812 -0.55917271
-0.76683500
9 10
-0.97449729 -1.18215958
fitted(lm(y ~ x, na.action=na.exclude))
1 2 3 4 5 6
7
0.68680104 0.47913875 0.27147646 0.06381417 -0.14384812 NA
-0.55917271
8 9 10
-0.76683500 -0.97449729 -1.18215958
Andy
From: Luca Wacker Hi, To obtain estimates for some missing values in my data I fitted a linear regression and then used the command fitted(model) to get the fitted values from the model, but R doesn't return any values for the NA's. I can calculate the fitted values from the estimates obtained from the summary of model, but that's not very handy. Is there a way to include the missing values in the analysis and get fitted values for the NA's? I tried to use with the function na.action, but that didn't work. thanks Luca
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