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.(The actual effect depends on your printer.) Choosing the Print in Black20 539671 ch16.qxd 8/28/03 10:04 AM Page 359Chapter 16 &' Getting Started Making Charts359and White option prints the data series with black-and-white patterns rather thancolors.Most noncolor printers handle this fine, even if this option is not set.But youmay want to experiment to determine the best output quality for your printer.Understanding Chart TypesPeople who create charts usually do so in order to make a point or to communicatea specific message.Often, the message is explicitly stated in the chart s title or in atext box within the chart.The chart itself provides visual support.Choosing the correct chart type is often a key factor in making the message com-pelling.Therefore, it s often well worth your time to experiment with various charttypes to determine which one is most effective.In almost every case, the underlying message in a chart is some type of comparison.Examples of some general types of comparisons include&' Compare item to other items: For example, a chart may compare sales ineach of a company s sales regions.&' Compare data over time: For example, a chart may display sales by monthand indicate trends over time.&' Make relative comparisons: An example is a common pie chart that depictsrelative values in terms of pie  slices.&' Compare data relationships: An XY chart is ideal for this.For example, youmight show the relationship between marketing expenditures and sales.&' Frequency comparison: A common histogram, for example, can be used todisplay the number (or percentage) of students who scored within a particu-lar range.&' Identify  outliers or unusual situations: If you have thousands of datapoints, creating a chart may help identify data that is not representative.Choosing a chart typeA common question among Excel users is  How do I know which chart type to usefor my data? Unfortunately, there is no cut-and-dried answer to this question.Perhaps the best answer is a vague one: Use the chart type that gets your messageacross in the simplest way.Figure 16-16 shows the same set of data plotted by using six different chart types.Although all six charts represent the same information (monthly Web site visitors),they look quite different from one another.20 539671 ch16.qxd 8/28/03 10:04 AM Page 360Part III &' Creating Charts and Graphics360Figure 16-16: The same data, plotted by using six chart types.The column chart (upper left) is probably the best choice for this particular set ofdata because it clearly shows the information for each month in discrete units.Thebar chart (upper right) is similar to a column chart, but the axes are swapped.Mostpeople are more accustomed to seeing time-based information extend from left toright rather than from top to bottom.The line chart (middle left) may not be the best choice because it seems to implythat the data is continuous  that points exist in between the 12 actual data points.This same argument could be made against using an area chart (middle right).The pie chart (lower left) is simply too confusing and does nothing to convey thetime-based nature of the data.Pie charts are most appropriate for a data series inwhich you want to emphasize proportions among a relatively small number of datapoints.If you have too many data points, a pie chart can be impossible to interpret.The radar chart (lower right) is clearly inappropriate for this data.People are notaccustomed to viewing time-based information in a circular direction!Fortunately, changing a chart s type is a very easy procedure, so you can experi-ment with various chart types until you find the one that represents your data accu-rately and clearly  and as simply as possible.20 539671 ch16.qxd 8/28/03 10:04 AM Page 361Chapter 16 &' Getting Started Making Charts361The remainder of this chapter contains lots of information about Excel s variouschart types.The examples and discussion may give you a better handle on deter-mining the most appropriate chart type for your data.Standard chart typesWhen you use the Chart Wizard to create a chart, the first step is to select the typeof chart.The first step of the Chart Wizard dialog box contains two tabs: StandardTypes and Custom Types.Selecting an item in the Chart Type list box displays a num-ber of subtypes for the chart type.For example, a Column chart has seven subtypes.The remainder of this section discusses each of Excel s standard chart types andshows examples of each.On theAll the subsequent examples are available on this book s companion CD-ROM.CD-ROMColumn chartsColumn charts are one of the most common chart types.A column chart displayseach data point as a vertical column, the height of which corresponds to the value.The value scale is displayed on the vertical axis, which is usually on the left side ofthe chart.You can specify any number of data series, and the corresponding datapoints from each series can be stacked on top of each other.Typically, each dataseries is depicted in a different color or pattern.Column charts are often used to compare discrete items, and they can depict thedifferences between items in a series or items across multiple series.Excel offersseven column-chart subtypes.Figure 16-17 shows an example of a column chart that depicts annual sales for twoproducts [ Pobierz całość w formacie PDF ]