* PS3.1, using data file DATA3-1, for various examples in Chapter 3  
read(data3-1) price sqft 
* estimate model and save things
ols price sqft / pcov resid=ut predict=phat1
print price phat1 ut
* another way to get fitted value  
genr phat2 = price - ut 
print phat2
* retrieve number of obs.  gen1 generates a single value.
gen1 n = $n
* retrieve ESS - Section 3.4  
gen1 ESS = $SSE
* compute st. dev. for price  
stat price / stdev=sdy
* compute TSS - Example 3.4  
gen1 TSS = (n-1)*sdy*sdy 
* compute RSS  
gen1 RSS = TSS - ESS 
* retrieve R-square  
gen1 RSQ = $r2
* print values  
print TSS ESS RSS RSQ  
* F-statistic in Example 3.6  
gen1 Fc = RSS*(n-2)/ESS
print Fc  
* plot price and phat against sqft 
plot price phat1 sqft
* Reproduce predicted averages in Table 3.1 using only 3 decimals  
genr phat3 = 52.351+(0.139*sqft)
print phat3  
stop