Hi all! Here are my Workshop 5 codes.
Download Triangle.csv here
Question 1
tri <- read.csv("Triangle.csv")
str(tri)
## 'data.frame': 14 obs. of 3 variables:
## $ Store : int 1 2 3 4 5 6 7 8 9 10 ...
## $ AvgDispIncome: num 22.3 36.6 55.5 46.7 32.4 31.7 41.6 21.4 44.4 34.1 ...
## $ Sales : num 3.7 3.9 6.7 9.5 3.4 5.6 3.7 2.7 5.5 2.9 ...
attach(tri)
# 1a.
plot(AvgDispIncome, Sales,
main = "Graph of Sales '$M against Average Disposable Income '$000")
fit <- lm(Sales~AvgDispIncome)
abline(fit, col = "red")
# 1b.
cor(AvgDispIncome, Sales)
## [1] 0.6982346
# 1c.
fit
##
## Call:
## lm(formula = Sales ~ AvgDispIncome)
##
## Coefficients:
## (Intercept) AvgDispIncome
## -1.9412 0.1929
# 1d.
summary(fit)$r.squared
## [1] 0.4875316
# 1e.
# residual analysis
par(mfcol = c(2,2))
plot(fit)
par(mfcol = c(1,1))
# 1f.
summary(fit)$coefficients[2,4]
## [1] 0.005480622
Question 2
summary(fit)$r.squared
## [1] 0.4875316
detach(tri)
# Explain Question 3 & 4 with logics