Line Graph

Scatterplots are used to display the relationship between a quantitative response variable and an ordered explanitory variable. Connecting the points in a scatterplot with lines produces a line graph. Line graphs are commonly used with financial data or when Time is the explanatory variable.

A Simple Line Grap

The code below uses the USPersonalExpenditure dataset to create a simple line graph with Year on the x-axis and U.S. Personal Expenditures in billions of dollars on the y-axis. There are separate lines for each type of personal expenditure.

library(ggplot2)
line_plot <- data_tbl %>% 
  ggplot(aes(x = Year, y = Amount, color = Expenditure, group = Expenditure)) + 
    geom_line() + 
    xlab("Year") + 
    ylab("Billions of Dollars")  +
    ggtitle("U. S. Personal Expenditures")
line_plot

You can add points to the plot with the geom_point() function

line_plot + geom_point()

Mathematicss, Computer Science, and Statistics Department Gustavus Adolphus College