Final answer:
Investigators must consider the population of interest and ensure good internal and external validity in their research.
Step-by-step explanation:
Investigators must carefully consider the population of interest in their research and ensure that their design has good internal and external validity.
Considering the population of interest is important because it helps to ensure that the findings of the study can be generalized to the larger population. By selecting a representative sample from the population of interest, researchers can make accurate conclusions about the entire population.
Internal validity refers to the extent to which a study can confidently attribute the observed effects to the independent variables being tested. Good internal validity is important because it allows researchers to make causal inferences.
External validity, on the other hand, refers to the degree to which the findings of a study can be generalized to other populations or situations. Ensuring good external validity is important because it allows researchers to apply their findings to real-world contexts.