Spreadsheet software is one of the most commonly used technologies for collecting, computing, and displaying data. Spreadsheets were developed as a way of organizing numeric data, by using an electronic table of rows and columns, and of creating business models, graphs and charts, and reports for financial, statistical, or other data.

SPREADSHEET PACKAGES

Spreadsheet packages are available for mainframes, minicomputers, and personal computers. Versions are available for various operating systems, including DOS, Windows (various versions), Macintosh, Unix, Java, Linux, and VMS. Spreadsheet capabilities are included in financial management packages as well as in integrated software packages. Dozens of spreadsheet software packages are available to users. The best-known packages are Microsoft Excel, Lotus 1-2-3, and Corel's Quattro Pro. These three packages are included as parts of integrated packages or suites from Microsoft Corporation, Lotus Development Corporation (owned by IBM Corporation), and Corel Corporation. In addition, dozens of other spreadsheet packages are available, many as "shareware," which offers a user an opportunity to try the product for a limited period and then pay a fee for permission to use the package beyond the evaluation period. Various spreadsheets are listed on the Internet by their developers, either as shareware or for purchase, and some are available for downloading.

SPREADSHEET APPLICATIONS

A spreadsheet is a table representing information in a worksheet form. It can be visualized as a large sheet of paper with rows and columns, and is based on the worksheets used by accountants for manual computations. A spreadsheet can range from a small, simple text table to a large document that can carry out complex computations and statistical analysis of thousands of data entries (Shelly et al., 1998). Simple spreadsheets can be displayed on-screen; more complex spreadsheets extend into vast numbers of cells and can be partially displayed on screen. The power of a spreadsheet is in its ability to store formulas and display their results. A recalculation feature in spreadsheets allows a user to enter new data into the spreadsheet, which can affect other sections of the spreadsheet, and see the results of new calculations. This "what if" feature of spreadsheets is a valuable tool for users.

FORMAT OF A SPREADSHEET

Spreadsheet software packages organize numeric data into table format, vertically in columns and horizontally in rows. Three types of data may be entered into a spreadsheet or worksheet: (1) values or numbers, (2) names or labels, and (3) formulas for calculation. Values may be used for basic arithmetic operations: addition, subtraction, multiplication, or division. Labels identify the information in the worksheet and help to organize it. Formulas perform calculations on data and display and store the resulting values. A cell, the intersection of a row and a column, can contain a label. a value, or a formula for performing calculations.

Only a small part of a spreadsheet is displayed on the screen at one time. Spreadsheets can contain millions of cells in each spreadsheet, and a spreadsheet file can include multiple spreadsheets. For example, the Lotus 1-2-3 (Lotus 1-2-3 Millennium, 1999) and Microsoft Excel (Getting Results with Microsoft Office 97, 1998) spreadsheets have 256 columns and 65,536 rows. Each spreadsheet thus can contain millions of cells of information. A spreadsheet file also may include multiple worksheets. Spreadsheets are very powerful, extensive electronic worksheets.

A spreadsheet handles such simple functions as adding, subtracting, multiplying and dividing. Arithmetic operators are used to represent the functions: addition (+), subtraction (-), multiplication (×), and division (÷). For example, an entry into cell D3 of "+ B3 + C3" would instruct the spreadsheet to sum the contents of cell B3 and C3 and store the sum in cell D3. A symbol at the beginning of a formula identifies the entry as a formula instead of a label. In the example = B3 + C3, the equals sign identifies the entry as a formula.

A simple spreadsheet can be enhanced with tools provided in the spreadsheet. Font styles(e.g., boldface), type sizes, and typefaces can be changed, color can be added to the background of cells or labels, and graphs can be used to illustrate data shown in the spreadsheet.

A spreadsheet is initially set up by default with a given column width, row height, and format for entries. If labels are longer than the column width allowed, the spreadsheet does not "lose" the extra characters; instead they are not displayed if the cell to their right has an entry. The user may change the column width and row height to enhance the appearance of the entries. Values are stored by the spreadsheet in their simplest form initially; an entry of $1050.00, for example, will be stored as 1050. The user then has tools within the spreadsheet for formatting those entries. Numeric data may be formatted as dollars and cents, with commas separating hundreds and thousands, in various formats for different

countries, with a given number of decimal points, in exponential form, or in other formats. When a formula is entered, the cell displays the result of computations. However, the formula itself is retained. To display the formula itself, not its results, in a cell, a user can choose a format for "text." A formula that is entered as + C3 + D3 - E3, for example, might show a result of 25. If the cell is formatted to the "text" format, the formula will show instead of the computed answer.

A set of data can be described to the spreadsheet by specifying the beginning cell, in the upper-left corner of the data, and the ending cell, in the lower-right corner of the data. For example, to identify a rectangle that begins with cell A1 and extends down to cell D3, the address of the range would be A1 … D3. Spreadsheets identify the range with a symbol that means "through." In the example A1 … D3, the format used by many spreadsheets, the range would be interpreted as "Cell A1 through Cell D3."

An example of a spreadsheet is shown in Figure 1. Rows 1 through 10 show a spreadsheet; rows 11 through 20 are a duplicate of that spreadsheet, with the text of formulas shown in rows 17 through 20. In row 3, BUDGET FOR FIRST QUARTER, the heading for the entire worksheet, is an example of a label. The column headings and items in column A are labels; columns B through D are values, which are summed in column E with formulas. The formulas in Column E sum the numbers for January, February, and March for each item. Across the bottom of the spreadsheet, the "Total" line is also a result of using formulas to sum the columns.

The heading, "BUDGET FOR FIRST QUARTER," and the column headings show how font changes can enhance the readability and attractiveness of a spreadsheet. Cells can be formatted to boldface, underline, or italicize entries; background color or shading can be added; and typefaces and sizes can be changed. In the sample worksheet, the main and column headings have been boldfaced for emphasis.

Values can be formatted. In the sample spreadsheet, the values in rows 7 through 10 have been formatted to two decimal places with commas. A user can select the desired formatting from a menu.

Spreadsheet data can also be selected for charts, or visual representations of those data. Cells are selected by highlighting them. Spreadsheet packages may chart one set of data in the

form of a pie chart, or two or more sets of data in bar charts (with vertical bars, horizontal bars, or stacked bars), line charts, area charts, or mixed charts, which combine bars and lines to represent data. They can be displayed in two-dimensional or three-dimensional form. Charts become part of the spreadsheet and may be stored on the same page as the spreadsheet or as a separate page or worksheet. A sample chart for the budget spreadsheet described above is shown in Figure 2.

The chart depicts the total figures from cells E7 through E9 in the spreadsheet, categorized by cells A7 through A9. A pie chart is only one of several choices of charts that could be used. The software provides steps for adding a heading to the chart and a legend, or listing of the labels for the charted data.

MACROS IN SPREADSHEETS

A macro is a series of commands that automate a spreadsheet task, streamline complex procedures, or create applications. For example, a macro to insert the user's name, company name, and date into worksheets can be stored and used repeatedly. A user can enter a macro into a worksheet file or into a macro library, a worksheet file that contains macros. To create a macro, the user enters the commands needed to carry out a task, gives the macro a name, and saves it in a file. To use the macro, the user selects it by name from a menu and asks the spreadsheet to run it. The steps are carried out automatically. For complex tasks that are used often, a macro makes it easier for a user to avoid mistakes in the task, since the steps are stored as a file and recalled as needed.

SPREADSHEETS IN INTEGRATED PACKAGES

Integrated software packages, which contain several kinds of software within one, usually include a spreadsheet. Information can be copied from a spreadsheet into other software packages, such as a word-processing package. Spreadsheets can be linked to files in other software in the package so that changes made in the spreadsheet are automatically reflected in the linked document. For example, a table from a spreadsheet could be linked to a word-processing document so that any changes in cell entries in the spreadsheet change the contents of the table in the word-processing document. This feature makes the spreadsheet a very powerful tool for analysis and reporting of data in various formats.