Introduction to the Windows Version of Minitab
This introduction will cover the following topics:
Getting in and out of Minitab
Double-click on the MINITAB 11 for Windows icon. The window will fill the screen and will be overlaid by a Session window and a Data window. Note that the Minitab window has a menu bar; you can click on Windows from this menu bar to choose either the Session or Data windows (among others). You can enter and examine data in the Minitab worksheet in the Data window and enter commands in the Session window. In a typical Minitab session, you will move between these windows many times. Regardless of which window you are currently using, you may want to resize it so that if fills the screen (see Windows Tutorial). We will be making choices from the menu bar in order to manage files, execute commands and produce graphs in Minitab.
To exit Minitab, pull down the File menu and choose Exit. If you have entered data during your session, dialog boxes will appear to confirm whether or not you want to save your current worksheet and then your current session. Click No or Yes appropriately.
Conducting a Minitab Session
Minitab sessions are interactive; data is first entered, generated or read into the Minitab worksheet and then manipulated or analyzed through a series of interactive commands. We will enter a small data set (a sample class roll) and demonstrate some Minitab commands.
| Anderson | 9 | 8 | 91 | |
| Byron | 9 | 7 | 82 | |
| Cather | 10 | 7 | 85 | |
| Dos Passos | 8 | 6 | 71 | |
| Eliot | 7 | * | 61 | |
| Faulkner | 5 | 10 | 84 | |
| Grego | 9 | 10 | 95 | |
| Hemingway | 10 | 9 | 90 | |
| Inman | * | 7 | 63 | |
| Johnson | 8 | 8 | 81 |
Enter the 10 names in the Data window under C1. Note that C1 changes to C1-T because text (or character data) has been entered in that column. In the space below C1-T, you can enter Student as a column label. Move to the Session window; commands are entered at the command prompt (MTB>) and executed by pressing the Enter key. Use the SET command in the Session window to add HW1, HW2 and Test 1 in columns 2 through 4; here is the code for C2:
Set C2 9 9 10 8 7 5 9 10 * 8 '*' is the missing value code in Minitab End
Label C2 through C4 appropriately in the Data window. Pull down the Graph menu and choose Histogram... The dialog box contains many options but you can simply enter a column number (say C2) in the Graph variables box to obtain a default histogram display. You may also experiment with other graphics commands such as Boxplot..., Plot... (for a scatterplot) or Character Graphs (for a stem-leaf). Pull down the Stat menu and choose Basic Statistics... then Descriptive Statistics.... Enter the columns of your choice in the Variables dialog box to obtain summary statistics such as the mean and standard deviation.
Return to the Session window. You can use the LET command to perform math operations on the columns. Arithmetic expressions used in the LET command are similar in syntax to those of traditional computing packages such as Fortran, PASCAL or C. Suppose you wanted to store the students' grade percentages in C5 and have the test percentage count 5 times the individual homework percentages. You would enter
Let C5=(10*(C2+C3)+5*C4)/7
Look at C5 in the DATA window to inspect your results.
Printing Output
Minitab has several types of output: high resolution graphics and printed output, line-printer graphics and program text from the Session window. All text output can be printed on the laser printer in the same way: Highlight the relevant section of text and choose Print Window... from the File menu. Click OK in the dialog box (the Selection option will already be chosen in the Print range box). To print high-resolution graphics, choose the relevant graph from the Windows menu then choose Print Window... from the File menu and proceed as when printing text.
Saving and retrieving text files
You will probably want to use data sets from one Minitab session to the next. If you have data that you would like to save to a floppy disk (inserted in drive a: of your computer), choose Other Files... and then Export Special Text... from the File menu. In the dialog box you obtain, enter the columns you want to save in the Columns to Export dialog box and click OK. Choose 31/2 Floppy (A:) from the Save in and type the filename you want in the File Name box. Click OK and the file should be saved on your floppy disk. These options are also available for any text in your Session window. To retrieve a data set , choose Other Files... and then Import Special Text... from the File menu in the appropriate window and enter information in the same way as when saving files.
Saving and retrieving Minitab Worksheets
In addition to saving data and text files, you can save Minitab worksheets, specially formatted files that contain not only the data, but variable names and other special attributes about your data set. Choose Save Worksheet from the File menu. In the dialog box you obtain, choose a: from the Drives: menu (you will have to scroll in order to see this choice), select a directory for the Directories: box and type the filename you want in the File Name: box. Click OK and the file should be saved on your floppy disk. To retrieve a worksheet, choose Open Worksheet ... from the File menu and proceed as when saving a worksheet.
You can use Save Worksheet As and Open Worksheet to save and read text files as well (it can be more convenient than Export Special Text and Import Special Text since the number of columns can be left unspecified). To get started, scroll through List Files of Type and select either .txt or .dat to open your data file (you will have saved them with either extension). You will need to click Options and modify options depending on whether your text file contains variable names, special delimiters, etc. When saving the worksheet, select Text under Save File as.