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Create a Data Table If you are interested in studying the effect a range of values has on the formula, you can set up a data table. This is a table that consists of the formula you are using, and multiple input values for that formula. Excel automatically creates a solution to the formula for each different input value. Do not confuse data tables with the Excel tables that you learned about in “Convert a Range to a Table.” A data table is a special range that Excel uses to calculate multiple solutions to a formula. Create a Data Table 1 Type the input values: To enter the values in a column, start the column one cell down and one cell to the left of the cell containing the formula, as shown here. To enter the values in a row, start the row one cell up and one cell to the right of the cell containing the formula. 1 2 Select the range that includes 3 the input values and the formula. 4 3 Click the Data tab. 4 Click What-If Analysis ( ). 5 Click Data Table. 5 2 180 12_577639-ch10.indd 180 3/15/10 2:46 PM 10 CHAPTER Analyzing Excel Data The Data Table dialog box appears. 6 Specify the formula cell you 7 6 want to use as the data table’s input cell: If the input values are in a column, enter the input cell’s address in the Column input cell text box. If you entered the input values in a row, enter the input cell’s address in the Row input cell text box. 7 Click OK. • What is what-if analysis? The technique called what-if analysis is perhaps the most basic method for analyzing worksheet data. With what-if analysis, you first calculate a formula D, based on the input from variables A, B, and C. You then say, “What happens to the result if I change the value of variable A?”, “What happens if I change B or C?”, and so on. Excel displays the results. When I try to delete part of the data table, I get an error. Why? The data table results are created as an array formula, which is a special formula that Excel treats as a unit. This means that you cannot move or delete part of the results. If you need to work with the data table results, you must first select the entire results range. 181 12_577639-ch10.indd 181 3/15/10 2:46 PM Summarize Data with Subtotals When you need to summarize your data, Excel offers a feature that enables you to quickly and easily add subtotals to a range of data. Although you can use formulas and worksheet functions to summarize your data in various ways, including sums, averages, counts, maximums, and minimums, if you are in a hurry, or if you just need a quick summary of your data, you can get Excel to do most of the work for you. The secret here is a feature called automatic subtotals, which are formulas that Excel adds to a worksheet automatically. Summarize Data with Subtotals 1 Click a cell within the range you want to subtotal. 2 Click the Data tab. 3 Click Subtotal ( ). 1 2 3 182 12_577639-ch10.indd 182 3/15/10 2:46 PM 10 CHAPTER Analyzing Excel Data 4 The Subtotal dialog box appears. 4 Click the At each change in 5 and then click the column you want to use to group the subtotals. 6 5 In the Add subtotal to list, click the check box for the column you want to summarize ( changes to ). 6 Click OK. • • Do I need to prepare my worksheet to use subtotals? Excel sets up automatic subtotals based on data groupings in a selected field. For example, if you ask for subtotals based on the Customer field, Excel runs down the Customer column and creates a new subtotal each time the name changes. To get useful summaries, then, you need to sort the range on the field containing the data groupings you are interested in. Excel calculates the subtotals and adds them into the range. Excel adds outline symbols to the range. Can I only calculate totals? No. The word “subtotal” here is a bit misleading because you can summarize more than just totals. You can also count values, calculate the average of the values, determine the maximum or minimum value, and more. To change the summary calculation, follow Steps 1 to 4, click the Use function , and then click the function you want to use for the summary. 183 12_577639-ch10.indd 183 3/15/10 2:46 PM Chapter 11 Visualizing Data with Excel Charts You can take a worksheet full of numbers and display them as a chart. Visualizing your data in this way makes the data easier to understand and analyze. To help you see your data exactly the way you want, Excel offers a wide variety of chart types, including pie charts, column charts, and stock charts. Excel also offers a large number of chart options that enable you to add chart titles and data labels, control the chart legend and gridlines, format the chart layout and style, change the chart type, and more. 13_577639-ch11.indd 184 3/15/10 2:47 PM Examining Chart Elements . . . . . . . . . . . . . . . . . . . . . . 186 Understanding Chart Types . . . . . . . . . . . . . . . . . . . . . 187 Create a Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Add Chart Titles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 Add Data Labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 Position the Chart Legend . . . . . . . . . . . . . . . . . . . . . . 192 Display Chart Gridlines . . . . . . . . . . . . . . . . . . . . . . . . . 193 Display a Data Table . . . . . . . . . . . . . . . . . . . . . . . . . . 194 Change the Chart Layout and Style . . . . . . . . . . . . . . . . 195 Select a Different Chart Type . . . . . . . . . . . . . . . . . . . . 196 13_577639-ch11.indd 185 3/15/10 2:47 PM Examining Chart Elements A chart is a graphic representation of spreadsheet data that uses columns, points, pie wedges, and other forms to represent numbers from a select range. As the data in the spreadsheet changes, the chart also changes to reflect the new numbers. To get the most out of charts, you need to familiarize yourself with the basic chart elements. Category Axis Chart Title Data Marker The axis (usually the X axis) that contains the category groupings. The title of the chart. A symbol that represents a specific data value. The symbol used depends on the chart type. Data Series A collection of related data values. Normally, the marker for each value in a series has the same pattern. Data Value A single piece of data. Also called a data point. Gridlines Optional horizontal and vertical extensions of the axis tick marks. These make data values easier to read. Plot Area Value Axis Legend The area bounded by the category and value axes. It contains the data points and gridlines. The axis (usually the Y axis) that contains the data values. A guide that shows the colors, patterns, and symbols used by the markers for each data series. 186 13_577639-ch11.indd 186 3/15/10 2:47 PM 11 CHAPTER Understanding Chart Types Excel offers 11 different types of charts, including column charts, bar charts, line charts, and pie charts. The chart type you use depends on the type of data and how you want to present that data visually. Although you must select a particular chart type when you first construct your chart, you can quickly and easily change to a different chart type later on if you need to. Chart Type Description Area A chart that shows the relative contributions over time that each data series makes to the whole picture. Bar A chart that compares distinct items or shows single items at distinct intervals. A bar chart is laid out with categories along the vertical axis and values along the horizontal axis. Bubble A chart that is similar to an XY chart, except that there are three data series, and in the third series the individual plot points are displayed as bubbles (the larger the value, the larger the bubble). Column A chart that, like a bar chart, compares distinct items or shows single items at distinct intervals. However, a column chart is laid out with categories along the horizontal axis and values along the vertical axis. Doughnut A chart that, like a pie chart, shows the proportion of the whole that is contributed by each value in a data series. The advantage of a doughnut chart is that you can plot multiple data series. Line A chart that shows how a data series changes over time. The category (X) axis usually represents a progression of even increments (such as days or months), and the series points are plotted on the value (Y) axis. Pie A chart that shows the proportion of the whole that is contributed by each value in a single data series. The whole is represented as a circle (the “pie”), and each value is displayed as a proportional “slice” of the circle. Radar A chart that makes comparisons within a data series and between data series relative to a center point. Each category is shown with a value axis extending from the center point. Stock A chart that is designed to plot stock market prices, such as a stock’s daily high, low, and closing values. Surface A chart that analyzes two sets of data and determines the optimum combination of the two. XY A chart that shows the relationship between numeric values in two different data series. It can also plot a series of data pairs in XY coordinates. (Also called a scatter chart.) 187 13_577639-ch11.indd 187 3/15/10 2:47 PM Create a Chart You can create a chart from your Excel worksheet data with just a few mouse clicks. As shown in “Understanding Chart Types,” Excel comes with 11 main chart types. However, each of these types has several predefined varieties, so in all Excel offers more than 70 default chart configurations, which means there should always be a type that best visualizes your data. Regardless of the chart type you choose originally, you can change to a different chart type at any time. See “Select a Different Chart Type” later in this chapter. Create a Chart 1 Select the data that you want to visualize in a chart. • If your data includes headings, be sure to include those headings in the selection. 1 3 2 Click the Insert tab. 3 Click a chart type. 2 188 13_577639-ch11.indd 188 3/15/10 2:47 PM 11 CHAPTER Visualizing Data with Excel Charts 4 • Excel displays a gallery of configurations for the chart type. 4 Click the chart configuration you want to use. • Excel inserts the chart. The tasks in the rest of this chapter show you how to configure, format, and move the chart. Is there a way to create a chart on a separate sheet? Yes. You can use a special workbook sheet called a chart sheet. If you have not yet created your chart, select the worksheet data, right-click any worksheet tab, and then click Insert to display the Insert dialog box. Click the General tab, click Chart, and then click OK. Excel creates a new chart sheet and inserts the chart. 189 13_577639-ch11.indd 189 3/15/10 2:47 PM