Answer:
Validity is the degree to which the research measures what it has to measure. High validity = Proper Research Design.
Reliability is the measure to which research measurement techniques are free of error or mistakes. High realiability = Reasearchers know the sample fully understands the question asked.
Representativeness is the extent to which consumers in a study are similar to the larger group of interest. High representativeness = Sample is large and chosen in an unbiased way.
