Problem Set 1

1. Problem Set 1 Troubleshooting

2. Log Files Save in text format for readability: log using ps1.log, replace or: log using ps1, text

3. Handling Missing Values • By default, Stata excludes all observations marked with a period (.) from subsequent statistical analysis. • Best practices: • Recode appropriate survey responses to missing. Safest: replace v1 = . if v1 == 6 • Do not drop observations with missing values. • Be careful not to recode missing values by accident.

4. Handling Missing Values Problematic: gen dummy1 = 0 replace dummy1 = 1 if v1 == 4 | v1==5 Safe: gen dummy1 = . replace dummy1 = 1 if v1 == 4 | v1==5 replace dummy1 = 0 if v1 <= 3 gen dummy1 = 1 if v1 == 4 | v1==5 replace dummy1 = 0 if v1 <= 3

5. Handling Missing Values Stata handles ‘.’ as higher than any integer value. Will recode missing observations: replace dummy1 = 1 if v1 > 6 Safe: replace dummy1 = 1 if v1 > 6 & v1 != .

6. Optional: PS2 Time Saver Stata supports loops: foreach x of numlist1800 1850 1870 1900 1920 1950 1970 1975 { sum spending if year==`x', detail } foreach x of varlistgdpcap pop taxhead race* { gen log_`x’ = log(`x’) sum `x’, detail hist `x’, name(`x’) }