Baseballs major leagues honor their outstanding first-year-players with the title “Rookie of the Year.” From 1949 to 1994, the overall batting average for Rookies of the Year was .285 far above the major league batting average of .260. However, Rookies of the Year don’t do so well in their second year- their overall bating average is .270. Baseball writers call this “sophomore slump” the idea being that star players get distracted by endorsements, television appearances, fame, etc and don’t perform as well. Does the data support the idea of sophomore slump? and why/why not?
I believe this has to do with calculating the r.m.s error for regression but I am not sure. Can you shed some light on how to reason the answer for this? Thanks you