
Appendix 2.1 Tabular and Graphical Presentations Using Minitab 75
Note that Minitab also provides the option of scaling the x-axis so that the numerical
values appear at the midpoints of the histogram rectangles. If this option is desired,
modify step 6 to include Select Midpoint for Interval Type and Enter 12:32/5 in the
Midpoint/Cutpoint positions box. These steps provide the same histogram with the
midpoints of the histogram rectangles labeled 12, 17, 22, 27, and 32.
Stem-and-Leaf Display
We use the aptitude test data in Table 2.8 to demonstrate the construction of a stem-and-leaf
display. The data are in column C1 of a Minitab worksheet. The following steps will gen-
erate the stretched stem-and-leaf display shown in Section 2.3.
Step 1. Select the Graph menu
Step 2. Choose Stem-and-Leaf
Step 3. When the Stem-and-Leaf dialog box appears:
Enter C1 in the Graph Variables box
Click OK
Scatter Diagram
We use the stereo and sound equipment store data in Table 2.12 to demonstrate the con-
struction of a scatter diagram. The weeks are numbered from 1 to 10 in column C1, the
data for number of commercials are in column C2, and the data for sales are in column C3
of a Minitab worksheet. The following steps will generate the scatter diagram shown in
Figure 2.7.
Step 1. Select the Graph menu
Step 2. Choose Scatterplot
Step 3. Select Simple and click OK
Step 4. When the Scatterplot-Simple dialog box appears:
Enter C3 under Y variables and C2 under X variables
Click OK
Crosstabulation
We use the data from Zagat’s Restaurant Review, part of which is shown in Table 2.9, to
demonstrate. The restaurants are numbered from 1 to 300 in column C1 of the Minitab
worksheet. The quality ratings are in column C2, and the meal prices are in column C3.
Minitab can only create a crosstabulation for qualitative variables and meal price is a
quantitative variable. So we need to first code the meal price data by specifying the class to
which each meal price belongs. The following steps will code the meal price data to create
four classes of meal price in column C4: $10–19, $20–29, $30–39, and $40–49.
Step 1. Select the Data menu
Step 2. Choose Code
Step 3. Choose Numerical to Text
Step 4. When the Code-Numerical to Text dialog box appears:
Enter C3 in the Code data from columns box
Enter C4 in the Store coded data in columns box
Enter 10:19 in the first Original values box and $10–19 in the adjacent
New box
Enter 20:29 in the second Original values box and $20–29 in the adjacent
New box
ApTest
Stereo
Restaurant
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