Imagine that it's the year 2030 and a new policy just went into effect in elementary schools in Los Angeles outlawing homework. Dr. Lee is interested in whether standardized test scores are affected by this policy. To do so, he compiles standardized test score data from 2027, 2028, and 2029. He then continues to track standardized test scores in 2031, 2032, and 2033. Dr. Lee then compares the test scores from the three years before the homework ban to the test scores from the three years after. To his surprise, he finds a significant increase in standardized test scores after the homework ban. What type of research design does this study illustrate? Imagine that it's the year 2030 and a new policy just went into effect in elementary schools in Los Angeles outlawing homework. Dr. Lee is interested in whether standardized test scores are affected by this policy. To do so, he compiles standardized test score data from 2027, 2028, and 2029. He then continues to track standardized test scores in 2031, 2032, and 2033. Dr. Lee then compares the test scores from the three years before the homework ban to the test scores from the three years after. To his surprise, he finds a significant increase in standardized test scores after the homework ban. What type of research design does this study illustrate? participant observer research Prospective ex post facto an interrupted time-series design a one-group pretest posttest design longitudinal developmental research