A study by the Readership Institute2 at Northwestern University used survey data to analyze how newspaper reader behavior was influenced by the Iraq war. The response variable was a Reader Behavior Score (RBS), a combined measure summarizing newspaper use frequency, time spent with the newspaper, and how much was read. Comparing RBS scores pre-war and during the war, the study noted that there was a significant increase in reading by light readers (mean RBS changing from 2.05 to 2.32) but a significant decrease in reading by heavy readers (mean RBS changing from 5.87 to 5.66). Identifying x = pre-war RBS and y = during-war RBS, explain how this finding could merely reflect regression toward the mean.