Uses

The mean can be used to represent the typical value and therefore serves as a yardstick for all observations.

For example, if we would like to know how many hours on average an employee spends at training in a year, we can find the mean training hours of a group of employees. This mean can then be used to compare against an individual’s annual training hours to judge if he has had comparable opportunity for training as his colleagues. Similarly, to compare the annual training hours of a smaller group against a more comprehensive group, their respective means can be used. An example would be comparing the mean number of annual training hours for women and for all employees.

The mean is useful for further calculations.

Say we were trying to find how much it would cost a company to give each worker a 5%-wage increase. This can be done even if we only know the mean wage of the company and the number of employees, but not the exact wage of each of them. Since the mean is just the total value divided by the number of data points, the total cost of a 5% wage increment for all workers sums up to 5% of the mean multiplied by the number of workers.