Analyzing Data, Part 1
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Analysis produces lists, frequencies, tables, statistics, and graphs from Epi Info or dBase files. Simple commands cause Analysis to select records using specified criteria, sort or list records, do frequencies or cross tabulations, do logical or mathematical operations on a variable, put the results in a new variable, and direct the results to the screen, a printer, or a disk file.

When you run Analysis from the main EPI menu, you see:

In the  lower section at the bottom, you enter commands, and in the larger section, the results of the commands appears. Information about data files and available memory is displayed at the top of the screen. At the bottom of the screen, some of the function keys are described.

Whenever the cursor is at the EPI6> prompt, commands may be entered from the keyboard. If you make a mistake or want to change part of the line being entered, use the Backspace or Left arrow key to return to the correct position and then enter the new material. The Delete and Insert keys work, deleting characters and turning the Insert mode on and off. The Home and End keys skip to the beginning or end of the current line.

Pressing the function keys shown at the bottom of the screen allow selection of help topics, commands, and variable names from lists that appear on the screen. After pressing one of the function keys, choose an item by moving the highlight bar with the up- and down-arrow keys and pressing Enter.

As results appear in the upper window, those that have scrolled out of sight at the top of the screen may be reviewed by pressing the Page Up and Page Down keys to move up and down one screen at a time. For finer movements, Control Page Up and Control Page Down will move one line at a time.

Entering Commands

Commands can be entered by typing the command in or by pressing a function key and then selecting the command or variables from a list. This is really nice when you're learning the system. Pressing F2 shows a list of the available commands:

Use the arrows keys to highlight the command that you want and then press the Enter key.

You can display general help by pressing F1 without anything on the command line, or you can see detailed instructions on a command by type the name of a command and then pressing F1. For example, to see what the MEANS command does, type in MEANS and press F1. Use the arrow keys or the Page Up and Page Down keys to move through the Help. When you're done reading it, press the ESC key to close Help.

Many commands require that you specify a variable (or variables) from a database to act upon. You can get a list of the currently available variables by pressing F3:

Again, use the arrows keys to highlight the variable  that you want and then press the Enter key.

Command Summary

Command	Description
Bar	Displays a Bar chart of a field
Close	Closes the databases currently opened.
Define	Creates a new variable for use in Analysis.There are three types of defined variables: standard, cumulative, and global. Standard variables are reset after each record is processed and are used for calculations that are performed with a record. Cumulative variables are reset after a new file is read and are used for things like summing a field. Global variables are only reset when leave the Analysis module.
Freq	Produces a table that shows how many records have each value of the variable.
List	Lists the records currently selected. You can limit the fields listed by including the names of the fields you are interested in.
Means	Shows the distribution of a numeric field, and optionally, the distribution based on another field. Additional statistics are provided.
Pie	Display a pie chart of a count of a field.
Read	Reads a database or dBase file into Analysis.
Recode	Used to group variables, translate codes from one system to another, or assign labels to numeric codes. A sample line is Recode Race to Racelabel 1=White 2=Black 3=Asian 4=Other Else=Missing. This convert the field Race (with numeric values of 1,2,3,4,5 to the variable Racelabel with values of White, Black, Asian, Other, and Missing.
Select	Narrows the records that are worked on. You enter an expression that must be true for the record to be included. Examples are SELECT AGE > 64 and SELECT SEX = "F". To clear a previous SELECT statement, just enter SELECT and press Enter.
Sort	Sort the current database by the field names supplied.
Tables	Displays a cross tabulation of the specified variables.

Using StatCalc  |  Getting Started With Epi Info  |  Analyzing Data, Part 2