How to make a dependent variable conditional on a binary variable?

[grantfel10]

Hi, I'm new to R and I'm not sure I phrased the question the right way. I'm running a multiple regression model with vote percentage as the DV. I would like to condition the DV on whether the party that received the votes is coded as populist (1) or not (0), so I can run the regression with just populist parties and then just non-populist parties. Is there a way to code the DV so that it is percentage of votes when 1?

[ADernild]

If I understand your question correctly, what you are looking for is a method to subset your data.frame, based on a binary variable. Luckily, base R has a function for this called subset. Here is an example using the built in dataset mtcars.

> head(mtcars)
                   mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

model_1 <- lm(mpg ~ cyl + disp + hp,
            data = subset(mtcars, vs == 1))

model_2 <- lm(mpg ~ cyl + disp + hp,
            data = subset(mtcars, vs == 0))

Hope this helps!

[grantfel10]

Thanks! That was exactly what I was looking for.