Introduction Minitab - Austincc.edu

Introduction to Minitab What Minitab Will Do for You Before the widespread availability of powerful computers and prepackaged statistical software, tedious manual computations were routine in statistics courses. Today, computers have revolu‐ tionized data analysis, which is a fundamental task of statistics. Packages such as Minitab allow the computer to automate calculations and graphs. Minitab can perform a wide variety of tasks, from the construction of graphical and numerical summaries for a set of data to the more com‐ plicated statistical procedures and tests described in The Basic Practice of Statistics, by David S. Moore. Minitab will free you from mathematical calculations and allow you to concentrate more on the analysis of data and the interpretation of the results. In this supplement, we will refer to the textbook as BPS. The numbering of exercises refers to exercises in BPS. Different Versions of Minitab This book is based on a pre‐release version of Release 15 for Windows, the most recent version of Minitab available. Different versions may look slightly different on the screen and require different methods of executing commands. Windows and Macintosh versions have menus that allow you to choose commands. In addition, all versions of Minitab allow you to type com‐ mands. This book will illustrate menu commands in detail. Session commands are listed in the Appendix. If you are using a version other than Release 15, there may be some differences in 1

2 Introduction to Minitab the menu interfaces. Manuals that come with the software as well as online help are available to give you more information. Beginning and Ending a Minitab Session To start a Minitab session from the menu, select Start h All Programs h MINITAB 15 English h MINITAB 15 English To exit Minitab, select File h Exit from the menu. When you first enter Minitab, the screen will appear as in the figure with a toolbar, a Session window, and a Data window. Additional windows such as graph windows and dialog boxes may also appear as you use Minitab.

Introduction to Minitab 3 The Minitab Worksheet The Minitab worksheet is arranged by rows and columns. The columns, C1, C2, C3, and so on, correspond to the variables in your data, the rows to observations. The columns can be viewed in the Data window. In addition, the worksheet may also include stored constants, K1, K2, K3, and so on. Most of the Minitab commands address the columns. In general, a column contains data for one variable, and each row contains all the data for a subject or observation. Columns can be referred to by number (C1, C2, C3, and so on.) or by name such as “height” or “weight.” In the Minitab worksheet, constants are referenced by the letter K and a number (K1, K2, K3, and so on). Unlike columns, constants are single values and do not show up in the data window. Storing a constant tells Minitab to remember this value; it will be needed later. Con‐ stants are analogous to the memory functions on most calculators. For instance, Minitab allows you to quickly find the average of a column of numbers. Instead of having to write it down, the value can be stored into a constant such as K1 and used in subsequent calculations. Minitab Commands Commands tell Minitab what to do. You can issue commands in Minitab by choosing com‐ mands from the menus or by typing session commands directly into the Session window. Menu commands are described throughout this guide. Session commands are an alternative to menu commands. They are described in the Appendix along with a list of session commands and their menu equivalents. To issue a menu command, click on an item in the menu bar to open the menu, then click on a menu item to execute the command, open a submenu, or open a dialog box. For ex‐ ample, to use Minitab’s calculator, select Calc h Calculator from the menu. The following dia‐ log box appears, prompting you for additional information needed to carry out the command.

4 Introduction to Minitab Dialog boxes may have text boxes, selection lists, and buttons. Many of the dialog boxes have buttons that lead to subdialog boxes. Most of Minitab’s dialog boxes have a variable list in the upper left corner. The list will include columns and constants from the current worksheet. To enter a variable in a text box, click or place the cursor in a text box. The variable list will now display only the valid choices for the text box. Click on the desired variable in the variable box and then click select or simply double click on the desired variable. You can also type the de‐ sired column or variable name into the text box. Minitab’s Calculator Minitab’s calculator lets you perform mathematical operations and functions. The results of a calculation can be stored in a column or constant. To use the calculator, choose Calc h Calculator from the menu. The dialog box shown on the previous page will appear. Under Store result in variable, enter a new or existing column or constant. Under Expression, select variables and functions from their respective lists, and click calculator buttons for numbers and arithmetic functions. You can also type the expressions. Minitab’s calculator performs the basic operations of addition ( ), subtraction ( ), multi‐ plication (*), division (/), and exponentiation (**). Many additional Minitab functions such as can be used as part of the expression in the calculator’s dialog box. The Data Window and Entering Data The Data window shows the columns in your worksheet and allows you to easily enter, edit, and view your data. To enter a value in a Data window cell, just click on the cell, type a value, and press Enter. To enter a column of data, click the data direction arrow in the upper left cor‐ ner of the worksheet to make it point down.

Introduction to Minitab 5 To enter a row of data, click the data direction arrow to make it point to the right. Enter your data, pressing Enter to move down or across. Press Ctrl Enter to move to the start of the next column or row. You can copy from cells, rows, or columns of the same or another data window. You can also copy from other applications such as spreadsheets or word processors. To copy to the Data window select Edit h Copy Cells from the Minitab menu or usually just Edit h Copy for other applications. To paste onto the data window, click on the upper left cell of the area where you want the data pasted and then select Edit h Paste from the Minitab menu. Opening, Saving, and Printing Files To open data from a file, select File h Open Worksheet from the menu. In the Files of type box, choose the type of file you are looking for: Minitab, Minitab portable, Excel, and so on. Select a file, and click Open.

6 Introduction to Minitab To print the contents of the data window, click on the data window. Then select File h Print Worksheet from the menu Select the desired options in the dialog box and click OK. Each data set you work with is contained in a worksheet. In Minitab Version 13, you can have many worksheets and graphs in one project. To save data as part of a project, select File h Save Project from the menu. To save data into a separate file, make the desired Data window active, and select File h Save Worksheet As from the menu. In Save as type, choose the data format in which you want the data to be saved. Select a directory, enter a file name, and click Save. Changing the Data Data in the data window can be corrected by simply clicking on a cell, typing in a correct entry, and hitting Enter. For more extensive changes, the Editor menu can be used. Under the Editor menu, you may choose to either insert cells, rows, or columns in the data set. To insert one or more empty cells above the active cell of the data window. select Editor h Insert Cells

Introduction to Minitab 7 from the menu. The remaining cells in the column move down. The number of cells inserted will be equal to the number of cells selected before you choose the command. To insert one or more empty columns to the left of the active column, select Editor h Insert Columns from the menu. Similarly, to insert one or more empty rows above the active row, select Editor h Insert Rows from the menu. The number of columns (or rows) inserted will be equal to the number of col‐ umns (or rows) selected before you choose the command. These commands are functional only when the data window is active. To move selected columns to before column C1, to after the last column in use, or to before a specific column select Editor h Move Columns from the menu. To delete in the Data window, columns, rows, or individual cells can be high‐ lighted and then deleted using the Delete key. Getting Help Documentation on Minitab features and concepts, written for users of menus and dialog boxes, can be obtained by clicking the Help button in any dialog box or pressing F1 at any time. For example, for help with Minitab’s calculator, click on the Help button on the Calculator dialog box shown on page 3. Help can be obtained from the menu by selecting Help h Help and then selecting a topic. A sample of the documentation available appears below.

8 Introduction to Minitab

9

To start a Minitab session from the menu, select Start h All Programs h MINITAB 15 English h MINITAB 15 English To exit Minitab, select File h Exit from the menu. When you first enter Minitab, the screen will appear as in the figure with a toolbar, a Session window, and a Data window.