Creating a density plot in R

Question

I am new in R and I am trying to create a density plot. I am looking to create a plot based on some regression analysis I have done earlier. So, basically, I want to see the relationship of Z to a,b and c variables that I have. All variables have values that range between 0 and 1 (numeric).

I have been trying to use ggplot to do the plot using the following code:

     dataset$test <- data.frame(a, b, c)
     ggplot(dataset, aes(Z, colour = test)) + geom_density()

I am not sure how I can group the a,b,c variables into 1 so I can use that in the colour of the ggplot function (see test variable)

When I run the ggplot I get this error: Aesthetics must be either length 1 or the same as the data (417): x, colour.

Can anyone help me develop this plot?

Thanks!

See the sample image of what I'm going for

It always helps to include the dataset in the question, or if it is too big, generate some sample. Can you run 'dput(dataset)` and add the output to your question? — Michael Harper
However my guess is that you are doing some wrong in the first line when creating dataset$test — Michael Harper
Hi Mikey, thanks for answering. I'm afraid the dput output is also too big. Is there something specific you need to know so I can tell you? But yes, I have a strong feeling that my test variable is not as it should be. So the issue I guess is to group the 3 variables into 1? — Chris M.
Are you sure that density is what you're looking for? I can see you want to see relationships between numeric variables. Density will give you the distribution of a specific variable. — AntoniosK
Hi Antoni, I have added a sample image of what I am trying to create. Please see the link above. I want to see the density of the data, so how the Z data distributes across those 3 variables in one chart. — Chris M.

AntoniosK AntoniosK · Accepted Answer · 2017-12-05T12:16:36

# example dataset
df = data.frame(a = rnorm(50, 5, 6),
                b = rnorm(50, 0, 1),
                c = runif(50,0,1))

library(dplyr)
library(tidyr)
library(ggplot2)

df %>%
  gather(var, Z) %>%                                  # reshape dataset
  ggplot(aes(Z, fill=var))+geom_density(alpha = 0.3)  # plot data

Creating a density plot in R

1 Answers