Relative frequencies / proportions with dplyr

Calculating Relative Frequencies / Proportions with dplyr

Ever wondered how to calculate the relative frequencies or proportions of different values within each group using the dplyr package in R? 🤔

Let's delve into this question using the mtcars dataset as an example.

The Problem

The problem we want to solve is calculating the relative frequency of the number of gears by the transmission type (automatic/manual) in one go using dplyr.

The Solution

Luckily, dplyr makes it incredibly easy to calculate relative frequencies with just a few lines of code. Here's how you can do it:

library(dplyr)
data(mtcars)
mtcars <- tbl_df(mtcars)

# Count frequency and calculate relative frequencies
relative_freq <- mtcars %>%
  group_by(am, gear) %>%
  summarise(n = n()) %>%
  mutate(rel.freq = n / sum(n))

print(relative_freq)

And that's it! 🎉

After grouping the data by transmission type (am) and number of gears (gear), we use the summarise function to count the frequency of each combination. Finally, we use mutate to create a new column called rel.freq where we divide the frequency n by the sum of frequencies within each group.

The Result

The resulting dataframe will look like this:

# A tibble: 4 x 4
# Groups:   am [2]
     am  gear     n rel.freq
  <dbl> <dbl> <int>    <dbl>
1     0     3    15 0.789474
2     0     4     4 0.210526
3     1     4     8 0.615385
4     1     5     5 0.384615

Now you have the relative frequencies for each combination of transmission type and number of gears! The rel.freq column provides the proportion of each combination within its group.

Call-to-Action

Are you excited to explore the power of dplyr further? Check out more of its amazing functionalities and start streamlining your data wrangling and analysis! 💪

Leave a comment below sharing your favorite dplyr tricks or any questions you may have. Let's geek out together! 😄