Problem:

One of the powerful attributes of a spreadsheet is the ability to predict from a dataset. Using the trendline feature of Microsoft Excel allows for a forecast to be created easily.

1. In cell A1, name the column referring to the values of the x axis.
2. Move to the right 2 columns and name the column referring to the y axis.
3. Below the title of the x values, insert each x value (one number per cell).
4. Below the title of the y values, insert each y value.
5. To graph these numbers select the top left hand corner, hold down the (Windows:right mouse button; Macintosh: mouse button), and move the mouse to highlight both columns of x and y values. Do not select cells in Row 1.
6. Go to the top menu to select Insert, then Chart. Another window will appear.
7. Select XY scatter for chart type. Press Next. Press Next again.
8. Type in the chart title. Type in the label of the x axis and the label to the y axis.
9. From the top menu of the window, select Gridlines. Select all major and minor gridlines. (All checks should be present.)
10. From the top menu, select Legend. Select show legend. (No check appears.)
11. Select Next at the bottom and then Finish.
12. Move the graph (if necessary) by selecting the graph with the mouse. Handles will appear on the edges of the graph. Use the mouse to move the graph to the desired location.
13. Values can then be erased and new values can be entered. The chart format will remain the same, but the x and y axis range of numbers will automatically change to fit the data.
14. To change the title of the graph, the x axis, or y axis, simply select the title and enter a new one.
15. To add a regression line or “line of best fit” select the data points on the graph and click the (Windows: right mouse button. When a pop-up menu appears, select add Trendline; Macintosh: click on data points, go to Chart menubar and add trendline.) Choose the type of line needed for the data.
16. To display the equation for the regression line, click on the trendline, (Windows: go to Options and select Display equation; Macintosh: go to Format, select Selected Trendline, Options, Display Equation on Chart.)