Answer to Question 1
Internal validity is the approximate truth about inferences regarding cause-effect or causal relationships. What does it really mean? Establishing internal validity is just a technical way of saying that you have ruled out plausible alternative explanations and have thus shown that a causal relationship likely exists between your program and the intended outcome. The key question in internal validity is whether observed changes can be attributed to your program or intervention (the cause) and not to other possible causes (described as alternative explanations for the outcome).
How do you go about establishing internal validity? One of the major ways is through the research design you apply. That is, a specific research design can address particular issues and help you eliminate the alternative explanations for your results, thereby enhancing the internal validity of your causal conclusions.
Answer to Question 2
B
Bronchoscopy. Figure illustrates physician using a bronchoscope to inspect the patient’s bronchial t
Mapping Dark Matter
Cortical Gray Matter in Monozygotic Twins Discordant for Schizophrenia
Areas of sclerosis (see arrows) in the white matter of a patient with MS.
The three states of matter: solid, liquid, and gas.
The Internal Anatomy of a Long Bone