Case 7: In the attached table are some data on the compensation of the executives of a certain company' The first column contains the \"command" levels in 8 ordered groups (8 corresponds to the \"top" executive and 1 to the lowest executive level); the second column contains the number of executives in each group; and the third column details the average salary of the executives of each group. Note the existing salary differences and present a reasonable explanation for them. EXECUTIVE SALARIES Scale of command Number of executives 3 Average salary (in S) 1 502.000 ? 3 323300 6 14 165.000 5 56 1 15.000 4 5'\" 59.000 3 819 49.000 c 889 40000 1 944 33.000