First things first: does the chart contain the right data, presented in the right way? You've already seen how to type data into the datasheet or copy-and-paste data into it from some other source. Now let's look at some other things you can do that affect the chart data.
The datasheet should appear automatically whenever you open the chart for editing (by double-clicking it). If it does not appear, or if you accidentally close it, you can reopen it by clicking the View Datasheet button on the Standard toolbar.
The sample chart starts you out with four columns and three rows of data. You can have more or fewer just by typing them into the datasheet grid or deleting from there:
To add a row at the bottom, simply type it in the first empty row. Type a label in the unlettered column at the left, and type the data in columns A, B, C, and so on. This adds a new category to the category axis of the chart.
To add a column at the right, type it in the first empty column. Type a label in the unnumbered column at the top, and type the data in rows 1, 2, 3, and so on. This adds a new series to the legend and a new color of bar to the chart.
To add a row above an existing row, or add a column to the left of an existing column, select the row or column that the new one should appear above or to the left of. To select it, click its number or letter. Then, choose Insert⇨Cells.
To delete a row or column, select it and press the Delete key.
By default, all the data in the datasheet appears in the chart. You might occasionally want to exclude certain data without removing it from the datasheet, however. (For example, perhaps you want to make a different version of the chart for a certain audience.)
To exclude certain data, select that range of cells on the datasheet and then choose Data⇨Exclude Row/Col. If you selected an entire row or column, the exclusion occurs immediately; if you selected only certain cells, a dialog box appears prompting you to choose Rows or Columns. (You have to exclude entire rows or entire columns, not just individual cells.) When excluded, the selected row(s) or column(s) turn gray and no longer appear in the chart (see Figure 11-4).
Figure 11-4: Columns A and B have been excluded.
You can also go the other way and include data that would not normally be included.
The legend displays the different data series, with a colored square representing each series. By default, the rows of the datasheet form the data series, but if you want, you can switch that around so the columns form the series. Figures 11-5 and 11-6 show the same chart plotted both ways so you can see the difference.
Figure 11-5: The data series are the people's names.
Figure 11-6: The data series are the months.
To switch back and forth between plotting by rows and by columns, click the By Row or By Column buttons on the Standard toolbar.
A chart can carry a very different message when arranged by rows versus by columns. For example, in Figure 11-5, the chart compares the performance of the people against each other for each month. The message here is competition-which person did the best? Contrast this to Figure 11-6, where the series are the months. Here, you're invited to compare one month to another for each person. The overriding message here is time-which was each person's personal best month? It's easy to see how the same data can convey very different messages; make sure that you pick the arrangement that tells the story you want to tell in your presentation.