For this pause-problem, consider the following study: a researcher would like to conduct an experiment to test the effectiveness of a program designed to raise sat scores. he wishes to obtain a sample of low-scoring high school students, administer the program, and then administer the sat again. he hypothesizes that sat scores will be higher after the program than before. pick out three potential validity threats to this study (internal or external) and describe what the researcher can do to limit each of those three threats