The best way to select a representative sample is through
random sampling method which is the best method for collecting a
sample. Random sampling provides equal opportunity to every member
of the population to be included in the sample which provides the
best representation.
The group of units or individuals who have a legitimate chance
of being selected are sometimes referred to as the sampling frame.
If a researcher studied developmental milestones of preschool
children and target licensed preschools to collect the data, the
sampling frame would be all preschool aged children in those
preschools. Students in those preschools could then be selected at
random through a systematic method to participate in the
study.