Microsoft Office Tutorials and References
In Depth Information
Calculating moving averages
Figure 17-17 The Moving Average tool helps smooth out bumpy curves to reveal the trend.
The Moving Average tool requires three pieces of information: the input range containing
the data you want to analyze, the output range where the averaged data will appear, and
the interval over which the data is averaged. To determine a three-month moving average,
for example, specify an interval of 3.
Figure 17-18 shows a six-month moving average superimposed over the original demand
curve chart shown in Figure 17-17. The Moving Average tool produced the data in
column C, which the Moving Average tool used to create the straighter plot line in the chart.
Notice that the first five cells in the tool’s output range contain #N/A error values. Where
the interval is n , you will always have n –1 #N/A error values at the beginning of the output.
Including those values in a chart presents no problem because Excel leaves the first area of
the plot line blank.
Figure 17-18 The Moving Average tool provides a better perspective of the overall trend.