STATA 11 for Windows SAMPLE SESSION - Food Security Group ...

Stata 11 Sample Session Section 3 – Tables and other Types of Analysis
Converting continuous variables to
indicator variables
the values in indicator variables are 0 and 1 or no/yes.
Examples of indicator variables are:
Is a person a citizen of the U.S.? (no/yes).
Does a farmer use fertilizer? (no/yes).
Stata can convert continuous variables to categorical and
indicator variables and it can also convert categorical variables to
indicator variables.
Suppose we want to create a new variable that indicates whether
a person is 18 years old or older. You could have generated a
new variable and assigned it a value of 1 if ca3 > =18. Then you
would need a second step to recode the system missing to 0.
There is another way to create this variable.
We will use the file c_q1a.dta. Open the file and then create a
new variable using the generate command following the steps
below:
1. Click on File then Open .
2. Select c_q1a.dta and click on Open. Copy the
command to the do-file editor. Delete the reference to
the directory.
3. Check to see if there are any missing values in the age
variable - ca3. Use the list command
list if ca3 >=.
We are checking to see if there are missing values
because Stata considers missing values to be
greater than any number.
4. Select Create or change variables from the Data
menu
5. Select Create new variable
The generate - Generate a new variable dialog box
opens.
6. Under the Main tab, type the name of the new
variable in the Generate Variable box: age18p
7. For the Contents box, type in
ca3>=18
8. Click on the Generate variable as type drop down
box and change to byte.
9. Click on the copy button, switch to the do-file editor,
paste the command, switch back to the dialog box and
click on Ok
10. Run a tabulate to look at the results.
Note: if there had been a missing value for an
observation, that observation would have been
assigned a value of 1.
It would have been better to put a qualifier on the command
to assign the values to cases where ca3 was not missing
(e.g. ca3 < .).
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