Suppose

that an independent study of middle-level managers employed at companies

located in Atlanta, Georgia, was conducted to compare the salaries of managers

working at firm in Atlanta to the salaries of middle-level managers across the

nation. The following data show the salary, in thousands of dollars, for a

sample of 15 middle-level managers employed at companies in the Atlanta area.

The

average marks of 80 students was found to be 40. Later it was discovered that a

score of 54 was misread as 84. Find the correct average marks.