# Exercise 

# plot the graph with fitted line
gnuplot  price sqft --output=display
# runs regression of sqft on prices
ols price const sqft
# saves the predicted values for the price
series yhat1=$yhat
gnuplot yhat1 sqft --output=display
# saves the residuals
genr resid1=price-yhat1
# generates the squared variable sqft
genr sqft2=sqft^2
gnuplot sqft resid1 --output=display
corr resid1 sqft
# OLS of sqft squared on prices
ols price const sqft2
series yhat2=$yhat
genr resid2=price-yhat2
corr resid2  sqft
gnuplot sqft resid2 --output=display
# calculating the impact of increasing the size of apartment on prices
scalar slope_2000=2*$coeff(sqft2)*2000