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4.3 The Scatter Chart
LEARNIN G OB JECTIVES
Construct a scatter chart to show the supply and demand curves for a market.
Learn how to adjust the scale of the X and Y axes of a scatter chart.
Add a trendline and line equation to a data series on a scatter chart.
This section focuses on the scatter chart type. What makes this chart different from the other charts
demonstrated in this chapter is that values are used on both the X and Y axes. So far, the charts we
have demonstrated in this chapter use categories or qualitative labels for the X axis. This means that
the distance between each category on the X axis will always be the same, even if numbers are used.
In a scatter chart, the X axis operates just like the Y axis. In other words, the distance between the
values on the X axis will vary depending on the value of the number. Depending on the format, we
can create the scatter chart to look just like a line chart. Since both the X and Y axes contain
quantitative values, the scatter chart is a valuable tool for studying various shapes or functional
forms for a line chart. In fact, a common feature used with the scatter chart is the trendline and
equation. Excel can evaluate the line that is produced on a scatter chart and produce a mathematical
equation. We will demonstrate these features in this section.
Supply and Demand: The Scatter Chart
Follow-along file: Continue with Excel Objective 4.00. (Use file Excel Objective 4.14 if starting here.)
A common use for a scatter chart is the study of supply and demand curves. This is because the data
points for both the supply and demand lines require quantitative values on both the X and Y axes. The Y
axis contains the price of a certain good or item; the X axis contains the quantity sold for that good or
item. Fundamental economic laws state that as prices rise, sellers are willing to increase supply and sell
more goods. However, the reverse is true for consumers. As prices rise, consumers purchase fewer goods.
The Supply & Demand worksheet contains hypothetical data for the supply and demand of breakfast
cereal. There are ten data points to show the change in supply and demand as the price changes in
Column A. The values you see in Columns A through C are formula outputs that are driven by the