R Tutorial: Adding aesthetics to represent a variable

Want to learn more? Take the full course at https://learn.datacamp.com/courses/intermediate-interactive-data-visualization-with-plotly-in-r at your own pace. More than a video, you'll learn hands-on coding & quickly apply skills to your daily work. --- In this lesson we'll review how to represent more than two variables on a single plot using the color, symbol, and size of glyphs. To begin, consider this scatterplot of national happiness against life expectancy. From the scatterplot, we see that happiness scores are positively associated with life expectancy, but the plot masks potential information provided by another variable, such as income classification. In this lesson, we'll explore how to represent an additional variable. Throughout this lesson, we’ll consider data from the World Happiness Report, which contains information about happiness levels across 141 countries. The data set consists of country-level happiness scores (where 0 is the lowest, and 10 is the highest), along with 8 explanatory variables, including world region, population, log GDP per capita, the World Bank’s income classification, healthy life expectancy, and indices of social support, freedom to make life choices, generosity, and freedom from corruption. Our goal is to create graphics to help us better understand national happiness. One approach to add a third variable to a scatterplot is to change the glyph—the geometric object drawn on our plotting canvas— to reflect the value of the third variable. For example, we can change the color of the points to reflect what income classification a country is in. To do this, we add a mapping in the add_markers() trace specifying that color should reflect the value of income. We see that the income classification further helps explain the observed association. Another way to encode a categorical variable on a scatterplot is to draw a different symbol for each category. To accomplish this we map our categorical variable to the plotting symbol,