Project values

You can fill in a series of values that fit a simple linear trend or an exponential growth trend by using the fill handle. To extend complex and nonlinear data, you can use the worksheet functions or the regression analysis tool in the Analysis ToolPak add-in.

Fill in values automatically

Select at least two cells that contain the starting values for the trend.
If you want to increase the accuracy of the trend series, select additional starting values.
Drag the fill handle in the direction you want to fill with increasing or decreasing values.
For example, if the selected starting values in cells C1:E1 are 3, 5, and 8, drag the fill handle to the right to fill with increasing trend values, or drag it to the left to fill with decreasing values.

Show Tip

To manually control how the series is created or to use the keyboard to fill in a series, use the Series command.

Select at least two cells that contain the starting values for the trend.
If you want to increase the accuracy of the trend series, select additional starting values.
Hold down the right mouse button and drag the fill handle in the direction you want to fill with increasing or decreasing values.
For example, if the selected starting values in cells C1:E1 are 3, 5, and 8, drag the fill handle to the right to fill with increasing trend values, or drag it to the left to fill with decreasing values.
Release the mouse button, and then click Growth Trend on the shortcut menu.

Show Tip

To manually control how the series is created or to use the keyboard to fill in a series, use the Series command.

Fill in values manually

Select the cell where you want to start the series. The cell must contain the first value in the series.
When you use the Series command, the resulting series replaces the original selected values. If you want to save the original values, copy them to a different row or column, and then create the series by selecting the copied values.
On the Edit menu, point to Fill, and then click Series.
Do one of the following:
- To fill the series down the page, click Columns.
- To fill the series across the page, click Rows.

In the Step value box, enter the value that you want to increase the series by.

Series type	Step value result
linear	The step value is added to the first starting value and then added to each subsequent value.
growth	The first starting value is multiplied by the step value. The resulting product and each subsequent product is then multiplied by the step value.

Under Type, click Linear or Growth.
In the Stop value box, enter the value you want to stop the series at.

Note If there is more than one starting value in the series and you want Microsoft Excel to generate the trend, select the Trend box.

Calculate trends by adding a trendline to a chart

You can create a trendline in a chart without creating the data for the trendline.

Click the data series to which you want to add a trendline or moving average.
On the Chart menu, click Add Trendline.
On the Type tab, click the type of regression trendline or moving average you want.
- If you select Polynomial, enter in the Order box the highest power for the independent variable.
- If you select Moving Average, enter in the Period box the number of periods to be used to calculate the moving average.

Notes

The Based on series box lists all the data series in the chart that support trendlines. To add a trendline to another series, click the name in the box, and then select the options you want.
If you add a moving average to an xy (scatter) chart, the moving average is based on the order of the x values plotted in the chart. To get the result you want, you might need to sort the x values before adding a moving average.

Project values with a worksheet function

Perform regression analysis with the Analysis ToolPak add-in

Function	Description
FORECAST	Project values
TREND	Project values that fit a straight trend line
GROWTH	Project values that fit an exponential curve
LINEST	Calculate a straight line from existing data
LOGEST	Calculate an exponential curve from existing data

When you need to perform more complicated regression analysis— including calculating and plotting residuals— you can use the regression analysis tool in the Analysis ToolPak add-in.

On the Tools menu, click Data Analysis.
If Data Analysis is not available, load the Analysis ToolPak.

How?
1. On the Tools menu, click Add-Ins.
2. In the Add-Ins available list, select the Analysis ToolPak box, and then click OK.
3. If necessary, follow the instructions in the setup program.
In the Data Analysis dialog box, click the name of the analysis tool you want to use, then click OK.
In the dialog box for the tool you selected, set the analysis options you want.
You can use the Help button on the dialog box to get more information about the options.