Homework 3

Read in data

election = read.csv("election.csv", header=TRUE, sep = ",")

Problem 2a

cor(election$growth, election$vote_pct)

## [1] 0.6499847

Problem 2b

incumbent_pct = lm(vote_pct ~ growth, data = election) 
incumbent_pct

## 
## Call:
## lm(formula = vote_pct ~ growth, data = election)
## 
## Coefficients:
## (Intercept)       growth  
##     49.6505       0.7969

Problem 2c

plot(election$growth, election$vote_pct, 
     pch = 16, 
     xlab="GDP Growth",
     ylab = "Incumbent Vote Percentage",
     main = "Growth vs. Vote PCT")

Problem 2d

df = as.data.frame(c(0,1,2,3,4,5))
colnames(df) = "growth"
df$pred = predict(incumbent_pct, df)
df

##   growth     pred
## 1      0 49.65054
## 2      1 50.44747
## 3      2 51.24441
## 4      3 52.04135
## 5      4 52.83829
## 6      5 53.63522