A group of investors follows the performance of 1000 companies. Ratings are assigned into one of 5 groups ...

A group of investors follows the performance of 1000 companies. Ratings are assigned into one of 5 groups: A=top 20%, B=next 20%, etc. The chart (see next page) shows the one year ratings for a sample of 60 of the largest companies. PART (1): Do the largest companies differ in performance from the performance of the 1000 companies in the Investor's ratings? Use alpha = .05

CHART: A=5, B=8, C=15, D=20, E=12