------------------------------------------------------------ | | Average Salaries of the Class and Year|Cases|-------------------------------------- | | 1st | 2nd | 3rd | 4th | |Quartile|Quartile|Quartile|Quartile ---------------+-----+-----------------+--------+----------- Mechanical '07 | 35 | $1800 | $1675 | $1362 | $1387 Mechanical '08 | 41 | 1450 | 1512 | 1512 | 1275 Mechanical '09 | 39 | 1375 | 1262 | 1313 | 1137 | | | | | Electrical '07 | 26 | 1750 | 1675 | 1675 | 1412 Electrical '08 | 36 | 2147 | 1437 | 1262 | 1262 Electrical '09 | 41 | 1462 | 1212 | 1387 | 1200 | | | | | Averages | | $1664 | $1462 | $1418 | $1279 | | | | | Percentages | | 100% | 87% | 85% | 76% ------------------------------------------------------------ If the separate classes be now considered the results are seen to be more or less irregular, although the general tendency is apparent. If the average results from all six classes are considered the results are more reliable as well as more uniform. The average salary varies in the same way as do the grades. If the average salary of the men of the first quartile ($1,664) be taken as a basis of comparison and considered one hundred per cent, then the salaries of the men in the second, third and fourth quartiles are respectively only eighty-seven, eighty-five and seventy-six per cent of this amount. In general terms, the salary of the men in the lower or poorest quarter of the class, from the point of view of school grades, will be only three-fourths the salary of the men in the upper or best quarter. The two middle quartiles will differ but little from each other, although the second has the advantage, by two per cent, or $44, over the third quarter. If the class be divided into a better and a poorer half, then the average salary of the men in the upper half is seen to be $1,563, while that of the men in the lower half is only $1,348. The men in the upper half earn $215 more in a year than the men in the lower half. This way of expressing the results is both clearer and more concrete than the mere statement of the coefficient of correlation.