English to Spanish Marketing Surveying

Definición:
A targeted sample is where a "sample" of the subject matter, be that people, plants/animals etc is selected using certain criteria, i.e. pregnant mothers between the ages of 25-30. Targeted samples are usually used by businesses or companies carrying out surveys on a particular group of people.

¿Conocen el equivalente en español? No lo puedo encontrar.
Gracias desde ya.