Let's say I have one data frame that consists of two samples. Assume there are no clusters or strata. The data set looks like this:
var1 var2 ... climate1 2 1 ... Warm2 2 3 ... Cold3 3 2 ... Warm4 1 1 ... Warm5 3 1 ... Cold...
There are different variables (var1, ...) and one indicator "climate", that tells you to which sample the rows/sampled units belong. There are no missings in the variable climate.
I created two survey design objects and I think this step is correct because the number of rows in the survey design objects differs.
svy.unw.1 <- svydesign(ids = ~1, data = plant[plant$climate == "Warm",] ) svy.unw.2 <- svydesign(ids = ~1, data = plant[plant$climate == "Cold",] )
Next, I created individual population margins looking like this:
var1.P1 <- data.frame(var1 = c(1,2,3), Freq = nrow(plant[plant$climate == "Warm",]) * c(0.2, 0.2, 0.6)) var1.P2 <- data.frame(var1 = c(1,2,3), Freq = nrow(plant[plant$climate == "Cold",]) * c(0.1, 0.1, 0.8)) ...
Then I raked the data.
svy.rake.1 <- rake(design = svy.unw.1, sample.margins = list(~var1, ~var2), population.margins = list(var1.P1, var2.P1))svy.rake.2 <- rake(design = svy.unw.2, sample.margins = list(~var1, ~var2), population.margins = list(var1.P2, var2.P2))
Now, here is my question:
Since there are two samples in the data frame "plant", will this part of the rake
function: sample.margins = list(~var1, ~var2)
choose the correct values of var1 and var2?
More specifically:Will the sample margins for svy.rake.1
/ svy.rake.2
be only selected from the rows of plant where plant$climate =="Warm"
/ plant$climate =="Cold"
?
I am unsure since I subsetted the data frame when creating the survey design objects, but in the rake
command there is no further specification of which rows to work with. What I don't want is that the whole data frame is used as a basis for the sample margins of the two distinct samples.
Note: Besides the issue of the two samples, I followed this instruction: https://www.r-bloggers.com/2014/04/survey-computing-your-own-post-stratification-weights-in-r/by Christoph Waldhauser.