When you open the Chart Wizard or the Chart Type dialog box, Line charts and XY (Scatter) charts look very similar in the Chart type list. In fact they are quite different, as you can see in the two charts shown here. It's important to choose the one that will work for you. Here are some guidelines to help you choose.
Line charts are good for displaying trends over time in such business numbers as sales, revenues, and profits. Use a Line chart if you want dates on the bottom of the chart, to make historical developments visible at a glance. Line charts usually have only one set of numbers, shown on the vertical axis.
An XY Scatter chart compares two sets of numbers at once, one on the horizontal X axis, one on the vertical Y axis. The data values are scattered across the chart. You have the option of connecting the values with lines, but those lines don't show trends over time.
XY Scatter charts are good for showing comparisons of numbers such as scientific or statistical data, where several measurements need to be plotted on a single chart. If you wanted to show how many cases of flu occurred in various age groups, or the average incomes in cities of various sizes, an XY Scatter chart would be an effective type.