Some purchasing specialist jobs also assign specialists to track the maintenance of office equipment. Maintaining records of warranties and service agreements is sometimes expected of a person in this position.
A retail price index would take this into account and use a weighted average which gives more prominence to commonly bought items. Excel does not contain a built in function to calculate a weighted average. It is however easy to do it using the SUMPRODUCT() function in a simple formula. SumProduct() multiplies two arrays (or ranges) together and returns the sum of the product. In the illustration it would calculate '(B4 x C4) + (B5 x C5) + (B6 x C6)'.
This formula adds all of the numbers and divides by the amount of numbers. An example would be the average of 1,2, and 3 would be the sum of 1 + 2 + 3 divided by 3, which would return 2. However, the weighted average formula looks at how relevant each number is. Say that 1 only happens 10% of the time while 2 and 3 each happen 45% of the time. The percentages in this example would be the weights. The weighted average would be 2.35. The weighted average formula is a general mathematical formula, but the following information will focus on how it applies to finance. Use of Weighted Average Formula The concept of weighted average is used in various financial formulas.