Question 5, Page #149

Question 6, Page #150
The trade-off between internal validity and external validity is that, if a researcher wants high internal validity, he/she has to settle for low external validity.
This is because, in order to establish internal validity, the researcher has to study the causal relationship in a tightly controlled laboratory environment. However, when the relationship is exposed to external factors in the real world, it is exposed to other unforeseen circumstances that can not be predicted in the laboratory environment which affects the cause-and-effect relationship between the dependent and the independent variables.



