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Exercise

Using stat_sum

In the Vocab dataset, education and vocabulary are integer variables. In the first course, you saw that this is one of the four causes of overplotting. You'd get a single point at each intersection between the two variables.

One solution, shown in the step 1, is jittering with transparency. Another solution is to use stat_sum(), which calculates the total number of overlapping observations and maps that onto the size aesthetic.

stat_sum() allows a special variable, ..prop.., to show the proportion of values within the dataset.

Instructions 1/4
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  • 1
    • Run the code to see how jittering & transparency solves overplotting.
    • Replace the jittered points with a sum stat, using stat_sum().
    • 2

      Modify the size aesthetic with the appropriate scale function.

      • Add a scale_size() function to set the range from 1 to 10.
    • 3

      Inside stat_sum(), set size to ..prop.. so circle size represents the proportion of the whole dataset.

    • 4

      Update the plot to group by education, so that circle size represents the proportion of the group.