Introduction

These demonstrations serve as a computer lab manual to acquaint students in beginning statistics classes with the use of Minitab software for making numerical and graphical descriptions of data. A few inferential procedures (confidence intervals and tests of significance) are also included. These may be skipped early in the course and revisited later on.

Before using Minitab, you should print out and read each of the five parts on your own to get oriented to what you will do on the computer and why. Then you will be ready to concentrate on how Minitab works and perhaps how to make slight variations in the procedures when you get to the lab.

Minitab worksheet: MTBDEM.MTW. Alternate data formats: MTP, TXT, XLS.

General Instructions:

• Parts 1-5 are available as Adobe Acrobat PDF files from the links above. This requires that you have an Adobe Acrobat reader installed on your computer (available free of charge from www.adobe.com).

• The Minitab worksheet MTBDEM.MTW should be readable in Minitab Releases 12 and later. If you follow the link to the worksheet using MS Explorer using a computer on which Minitab is properly installed, then Minitab should open automatically with the worksheet ready to use. Otherwise you can save the worksheet to a disk and open it according to the instructions at the beginning of Part 1.

  Note: If you have trouble opening MTBDEM.MTW in Minitab, then try MTBDEM.MTP or MTBDEM.TXT. If you are trying to use these data with software other than Minitab, then try MTBDEM.TXT or MTBDEM.XLS. (MS Excel uses statistical terminology differently from many statistical texts. Most relevant here, the graphical display called "dot plot" in Excel differs in form and appropriate uses from the dotplot in Minitab.)

• Text printouts of Minitab procedures were made using Minitab Releases 10-13 and some of them were edited to emphasize certain features or to fit pages; what you see on your computer screen may be a little different from what is shown in these notes. Graphics printouts were made In Minitab 13, sometimes with titles and footnotes not indicated in the procedures.

• Both Minitab commands and Minitab menus are illustrated. In order to use commands, you may need to follow the instructions at the beginning of Part 1 for enabling commands. Most of the instructions for using menus and probably all of the commands are compatible with Minitab 14.

• Minitab has two graphics modes, standard and professional. Standard mode makes graphs from text characters such as -, +, and *. Professional mode uses the plotting capabilities of Windows. When Minitab starts up, professional mode is in effect. The commands GSTD (for graphics standard) and GPRO (for graphics professional) allow you to toggle between modes. When making a graph, you may get a cryptic graphics-related error message. Usually, this means that you are trying to make a type of graph that has a mode opposite to the one in effect. Just type GSTD or GPRO and try again. (For some reason, character dotplots seem to be accessible in either mode.)