Scatter Plots II

Install and load ggplot

# install libraries 
# This demo requires the 'ggplot' package 
if( !is.element("ggplot2", installed.packages()[,1]) )
  install.packages("ggplot2")

# load libraries 
library(ggplot2)

Download and Load Data

download.file("http://www.openintro.org/stat/data/evals.RData", destfile = "evals.RData")
load("evals.RData")

Create Scatter Plot Function

# this function will create a plot of every variable in your data frame against your dependent variable
# the function takes two arguments: x = the name of your data frame and dv = the name of your dependent variable
# if you want to save the scatter plots as .png files define the file path for graphs_folder below 
# you will also need to remove the "#" from the two lines in the function that are commented out and place a "#" before print

# save graphs in this folder
graphs_folder <- 'filepath/graphs/'

scatter <- function(x, dv, na.rm = TRUE, ...){
  nm <- names(x)
  for (i in seq_along(nm)) {
  print(ggplot(x, aes_string(x = nm[i], y = dv)) + geom_point(color="dark blue") + theme_classic() +  stat_smooth(method = "lm", se = FALSE, size = 2, color="dark red"))}
    # plots <- ggplot(x, aes_string(x = nm[i], y = dv)) + geom_point(color="blue") + theme_classic() + stat_smooth(method = "lm", se = FALSE, size = 2)
    # ggsave(plots,filename=paste(graphs_folder, "scatter_",nm[i],".png",sep=""))}
}

Run Scatter Plot Function to Create Scatter Plots for an Entire Data Frame

scatter(x = evals, dv = "score")