#############################################
# Simple Regression and Plot Using SAT Data #
#############################################

# read in data
setwd("c:/Documents/Classes/Econ4230/R_and_Stata/")
library(readxl)
data = read_excel("Data/SATdata.xlsx")

# regression and plot
library(ggplot2)
results=lm(SAT~Income,data=data)
data$FittedValues = results$fitted.values
ggplot(data) + 
  geom_point(aes(Income,SAT)) + 
  geom_line(aes(Income, FittedValues, color ="red")) +
  ggtitle("SAT - Household Income Regression")

# print summary of OLS results
summary(results)