GENERAL INFORMATION ABOUT MINITAB

If you have any questions about this, send me a note at ... Dennis Roberts

Activating the Session Window MTB> Prompt
Up until Release 11 of Minitab, there was some concerted effort on the part of the Minitab documentation both in printed form and help screen form, to provide adequate overviews and examples of using BOTH menus and dialog boxes, AND session commands, for doing work. However, with Release 12, all bets seem to be off with regards to helping users ... particularly NEW users, to have access to and information about ... using commands to do Minitab work in the Session Window. Admittedly, there is some small attention to this in the documentation but, a new user will still have a very difficult time learning about this option ... unless an old time user tells him/her about it. For example, one illustration of how a new user will find it difficult to learn about using session window commands is that when the package is installed, the infamous MTB> prompt what appears in the Session Window ... is DISABLED. So, even if a new user had heard about using commands, the way the package comes 'fired up ready to go' is NOT with the MTB> prompt visible.

So, let' s first get this problem straightened out. TO ENABLE THE MINITAB PROMPT, in RELEASE 12 so when you turn on Mintab the prompt will appear in the Session Window, do the following:

  1. Get Release 12 Minitab running
  2. Pull down the Edit menu to Preferences
  3. Click on Session Window and then click Select
  4. At the top right, where it says Command Language ... click for ENABLE

You are done! Now, the MTB> prompt will appear in the Session Window for use.

Using Commands and/or Menus for doing Work
Now, there are TWO general ways in which you can navigate around in Minitab: 1) Use commands to carry out functions and routines, and 2) use pull down menus and dialog boxes. BOTH REQUIRE YOU TO UNDERSTAND WHAT IT IS YOU ARE DOING AND WHAT YOU WANT TO ACCOMPLISH. While I was weaned on Minitab using commands (which dates me) and I feel most comfortable in that realm, more recent versions of Minitab (since Releaste 9 which was the first true Windows version) have increasingly relied on and have expanded the use of Minitab using different windows for doing work, and accessing these windows and functions using menus and associated dialog boxes. For most of your work, you could opt for one method (commands) or the other (menus) to accomplish what you want to do. In the final analysis, it is YOU that has to decide which way will be most beneficial for your work. Actually, for myself, while I use commands most of the time, it would be more accurate to say that I use a 'combination approach' using commands when they suit me and using menus when THEY suit me. The important thing is to know that and practice with BOTH ways of doing work and that will allow you to better decide which approach is best for you.

Getting Data into the Minitab Worksheet
While there are ways to import data into the Minitab worksheet AND one could RETRIEVE worksheet files that have already been saved in Minitab, usually you have to enter data yourself into the worksheet, to get things started. So, how do we get data into the worksheet? There are TWO general ways.

One way is to go directly to the DATA WINDOW which will be the lower half of the split screen that you will see (unless you have changed this) if you have just installed Minitab on your system. If you maximize that part of the screen, you will have a full screen for entering data. Now, you enter data in the Data Window just like you do for most spreadsheets ... enter a value, hit the enter key, enter the next value, hit the enter key, etc. until you have finished entering all the data. NOTE: One little trick that can help you here is ... depending on which way you want to enter the data (number by number across the rows ... or number by number down the columns) ... you can change the little arrow in the upper part of the Data Window to the direction you want. If it is not the way you want to go when entering the data, click on it with the cursor ... and it will change to the other direction. So, if the arrow is pointing down, when you enter a value in a cell and hit the enter key, the cursor will automatically jump DOWN to the next lower cell in that same column. Also note that the very top row in the Data Window is for given names or labels to the data columns. When you are all through with entering the data, make sure you hit the enter key that final time. Then, you could either go to the Session Window to start doing work with the data using commands ... or you could use the pull down menus and dialog boxes to do your work.

The second way to enter data into the worksheet is to do it at the prompt in the Session Window. At the MTB> prompt, there are two commands that can help you here depending on whether you are putting in data into ONE column only or, have to enter data into several columns at a time (say 3 test scores for 10 different people ... rows are people and columns are the different tests. See the Minitab Session Window output below.


MTB > set c1

DATA> 10 8 9 2 6

DATA> end

MTB > read c2 c3

DATA> 10 9

DATA> 8 9

DATA> 2 7

DATA> 5 9

DATA> 4 6

DATA> end

      5 rows read.

MTB > prin c1-c3

Data Display



 Row     C1     C2    C3



   1     10     10     9

   2      8      8     9

   3      9      2     7

   4      2      5     9

   5      6      4     6

Now, at the MTB> prompt, you could use the command: MTB> set c1 ... and this would give you a DATA> prompt after you hit the enter key. It is on the DATA> line that you could enter your data ... like ... 10, 8, 9, 2, 6 ... or you could leave spaces between the values ... and when you type END on the next DATA> line ... you will have told Minitab to put those 5 values in c1. In addition, if you need to put data in more than one column at a time, you could use the READ command ... and note that I did: MTB> read c2 c3 .. and when you hit the enter key, you will again get the DATA> prompt ... but in this case, you MUST put 2 values on each line before hitting the enter key since Minitab is expecting to have 2 values on the line given that you asked it to READ two columns. If you don't, you will get an error message. Again, when you are done, you will enter END on the next DATA> line and then Minitab will put the data into c2 and c3. Now you are ready to work with the data.

Using Session Window Commands at the MTB> Prompt
Now, once you have data in the worksheet, you are ready to do whatever analyses are appropriate for your data. Here are two very simple examples of how you can get this done using the MTB> prompt. For example, every stat package has some command/routine that will calculate and print out a bunch of descriptive statistics: and Minitab is no exception. The command in Minitab for doing this is called DESCRIBE (NOTE: when using commands, you only have to use the first 4 letters of the command since Minitab does NOT read anymore than that.). So, to get the descriptive stats out for our 3 columns of data, you could simply at the MTB> prompt .... go MTB> desc c1-c3. The - inbetween the c1 and c3 tells Minitab to do all the columns between the two that are listed ... this is a shortcut if you have many columns to indicate. Note that when you use DESC c1-c3 at the prompt, you get out a variety of information about the variables such as the mean and standard deviations. 


MTB > desc c1-c3

Descriptive Statistics



Variable             N       Mean     Median     TrMean      StDev    SE Mean

C1                   5       7.00       8.00       7.00       3.16       1.41

C2                   5       5.80       5.00       5.80       3.19       1.43

C3                   5      8.000      9.000      8.000      1.414      0.632



Variable       Minimum    Maximum         Q1         Q3

C1                2.00      10.00       4.00       9.50

C2                2.00      10.00       3.00       9.00

C3               6.000      9.000      6.500      9.000
What if you wanted to make a simple frequency distribution of the data in c3? This calls for the use of a TALLY command in Minitab so, you would do MTB> tall c3 ... see the output below. 

MTB > tall c3



      C3  Count

       6      1

       7      1

       9      3

      N=      5
See that tally will order the values and then indicate how many (count) frequencies there are at each score value.

Using Menus and Dialog Boxes
We could accomplish the SAME identical outputs if we use menus and dialog boxes. Now, what if we want to do the descriptive stats on c1-c3? Here are the steps using the menus/dialog boxes.

dialog.jpg - 18456 Bytes

  1. Pull down the Stat menu to Basic Statistics
  2. Slide over to Descriptive Statistics: get a Des Stat dialog box like the one above
  3. In the dialog box that comes up, highlight the variables c1-c3 (just hold the left mouse button down as you scroll down over the 3 columns)
  4. Hit Select (and the columns jump to the Variables box
  5. Click OK
You get exactly the same output comared to doing MTB> desc c1-c3

Now, if you wanted to make the frequency distribution using tally? Do the following.

  1. Pull down the Stat menu to Tables
  2. Slide Tables over and down to Tally
  3. Click on c3 and Select
  4. Click OK

Again, you get the same output as you would doing MTB> tall c3. The funny thing about using the menus and dialog boxes is when you are done, the very first thing that comes out just before the output you want IS the command that you could have typed directly in at the MTB> prompt! (no little dig there on my part, right?)

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