# Smooth A Scatterplot Trend Line

Want to learn more? I recommend working through: R for Data Science, R Cookbook, and R Graphics Cookbook.

# load the ggplot2 library library(ggplot2) # set the seed so we can reproduce the results set.seed(1410)

# create a variable that is the first 100 rows of the diamonds dataset dsmall <- diamonds[sample(nrow(diamonds), 100), ]

# create a scatterplot with a smoothing line with a wiggly trend line p1 <- qplot(carat, price, data = dsmall, geom = c("point", "smooth"), span = 0.2); p1

geom_smooth: method="auto" and size of largest group is <1000, so using loess. Use 'method = x' to change the smoothing method.

# create a scatterplot with a smoothing line with a smooth trend line p2 <- qplot(carat, price, data = dsmall, geom = c("point", "smooth"), span = 1); p2

geom_smooth: method="auto" and size of largest group is <1000, so using loess. Use 'method = x' to change the smoothing method.