Look at the chart headings carefully to determine which value goes in the marked spaces:

$\backslash$table$[[,\backslash$table$[[$Positive$],[$Drug Test$]],\backslash$table$[[$Negative$],[$Drug Test$]],$Total,$],[\backslash$table$[[$Patient uses$],[$Drugs$]]],[\backslash$table$[[$Patient does not$],[$use drugs$]]],[$Total$,,,,v$