In cell R9, enter a formula using the AVERAGEIF function to determine the average number of years of experience for lifeguards.

Explanation:

The AVERAGEIF function is an excel function that is used to determine the average of a range of cells. It has the format

=AVERAGEIF(range, criteria, average_range)

The range is use to specify the range of cells that will be covered when calculating the average. like  R9:R20

The criteria is like the condition that a cell must meet in order for it content to be included in the calculation. Like for the formula for years of experience, the criteria might be the course of study. This show that anybody that does study a course will not be included in the average calculation.

Average_range maybe optional if the cell of the range is the cell in which the data to be considered is located. However, if the cell is different, then the average range is used to specify the range of the cell to be calculated. For example, R9:R20 might contain the names of the employees, while maybe p9:p20 contain their their course, then the average_range cells might contain the number of years of experience that will be calculated example Q9:Q20.

The formular can be =AVERAGEIF(R9:R20, p9:p20, Q9:Q20)

The number in each segment of the formula denotes the lowest range of cells while the second numbers after the colon is the highest range of cell you want.