X f f∙X $21,000​ 14 $294000 ​$23,500​ 12 ? ​$27,500​ 18 ? $31,500​ 3 ? $38,700 5​ ? ​$146,700 1 ? -------------------------- n = ? sum = ? Put numbers where the question marks are. Multiply each of the X-values by the f value to finish the f∙x list. (I did the first one, you do the others) Add the f column to get n Add the f∙x column to get the sum. Then divide the sum by n. That will be the mean salary. Edwin