Intro in Stata – Quiz 5

Quiz Question Explanations

Question 1

Enter the command ‘sum total_ely3 if total_ely1 == . & total_ely2 == .’

Question 2

Enter the command ‘sum total_ely3 if total_ely1 == . | total_ely2 == .’

Question 3

Enter the command ‘sum total_ely3 if total_ely1 != . & total_ely2 != .’ Alternatively you could enter ‘sum total_ely3 if !missing(total_ely1) & !missing(total_ely2)’

Question 4

First identify the 25th and 75th percentiles of baseline scores by running the command ‘sum total_bl, det’. You’ll see that the 25th percentile is 4 and the 75th percentile is 10. So you can calculate the average Year 3 score for students below the 25th and above the 75th percentiles with the command ‘sum total_ely3 if total_bl < 4 | total_bl > 10’.

While this command will give the correct answer, it requires you to view the values in the first command and manually enter them into the second command. This type of ‘hardcoding’ is prone to error, especially for numbers with lots of significant digits and in long pieces of code. A better approach would be to use macros as in the following command: sum total_ely3 if total_bl < `r(p25)’ | total_bl > `r(p75)’. This will be covered in the next lesson on Stata Best Practices.

Question 5

Run the command ‘count if (child_caste_cat == 2 | child_caste_cat == 3 | child_caste_cat == 4) & total_ely3 == 16’