# Regression
# Dennis E. Slice (c) 2012
# Income-Happiness
# Fake data

# Model parameters
plotTitle = "Happiness v. Income"
xLbl = "X (Income)"
yLbl = "Y (Happiness)"
n = 10 # Small n for illustrative purposes
b0 = 3 # non-zero intercept
b1 = 0.1 # one thousand in income increases happiness by 0.1
minX = 1 # minimum income
maxX = 100 # maximum income
rangeX = maxX - minX

# X - independent variable (free to vary)
income = seq(minX, maxX, rangeX/(n - 1)) # 1000 to 100000 in income
# (n-1)? This gives the number of gaps so the number of points will equal n

# Y - dependent variable, completely determined by x
happiness = b0 + b1 * income

# Generate some error = variation due to anything
# NOT in the model. E.g. sickness, marital status,
# lying about income, etc, etc, etc,...anything!
# sd=2 chosen by trial-and-error for illustrative purposes
error = rnorm(n, 0, 2) 
happiness = happiness + error

# Make a data frame and save it
df <- data.frame(income,happiness)
write.table(df,paste("happiness",n,".RData",sep=""))
plot(df$income,df$happiness)