Final answer:
Colby can conclude that his practice driving test has poor concurrent validity if it does not score similarly to the Mississippi Drivers Test. Concurrent validity refers to the measure of how well one test correlates with a benchmark or another test taken at the same time.
Step-by-step explanation:
When Colby administers the practice driving test and later compares scores on the test with students' scores on the Mississippi Drivers Test, the aspect of validity he is concerned with is concurrent validity. Concurrent validity is a type of evidence that assesses the correlation between the results of two tests that are administered at approximately the same time, or concurrently. If the scores on Colby's practice test do not correlate well with the actual Mississippi Drivers Test scores, he can conclude that the practice test has poor concurrent validity, meaning it is not a reliable tool for predicting or correlating with the current, established benchmark. In the context of the investigation regarding the effectiveness of a new math textbook, the groups compared are not independent but matched. This is because the same group of students is tested before (pretest) and after (posttest) the intervention of using the new textbook. Consequently, the study design is prospective, meaning it is designed to look forward and observe outcomes following the intervention.