Close the Chart Data editor to return to the chart.
When you add a chart, Pages defines the default data series for it. In most cases, if a table is square or if it’s wider than it is tall, the table rows are the default series. Otherwise, the columns are the default series. You can change whether rows or columns are the data series.
Click the chart, then click the Edit Chart Data button.
Click the row or column button in the top-right corner of the Chart Data editor.
If you want to see certain data points in your chart, you need to create the chart from a smaller table or a smaller selection of data from a large table.