Respuesta :
This is an example of STRATIFIED RANDOM SAMPLING.
Stratified random sampling refers to method of sampling in which the target population is first divided into smaller groups based on the features that are common to these groups. Random samples are then taken from these smaller groups.
Stratified random sampling refers to method of sampling in which the target population is first divided into smaller groups based on the features that are common to these groups. Random samples are then taken from these smaller groups.