Practical example 1

Dataset

StataData1.dta

Variable name	gpa
Variable label	Grade point average (Age 15, Year 1985)
Value labels	N/A

Variable name	sex
Variable label	Sex
Value labels	0=Man 1=Woman

sum gpa if sex==0

sum gpa if sex==1

Practical example 2

Dataset

StataData1.dta

Variable name	unemp_45
Variable label	Days in unemployment (Age 45, Year 2015)
Value labels	N/A

histogram unemp_45, freq

histogram unemp_45 if unemp_45!=0, freq

The first figure shows a histogram for unemp_45 – not very useful since there are so many individuals with the value 0. In the second histogram, the zeroes have been omitted so that it only shows individuals with at least one day in unemployment at age 45.