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Appendix B: Computer Resources 353
options under Bars Represent. Select option 1) Counts of Unique Values, if you
have one or more columns of categorical data (as is the case in Example B.8).
Select 2) A function of a Variable if you have one or more columns of measurement
data, or select option 3) Values from a Table if you have one or more columns
of summary data. For each of these options there are several other options
for representation of the graph. Choose one of the appropriate choices and then
click OK. Now another dialog box appears entitled Bar Chart – [Description].
In this dialog box enter the variable name/s under Categorical Variables. If you
have not entered the names of the variables in the data columns, then under
Graph Variables just enter C1, C2, and so on, and then click OK. A separate graph
is displayed for each variable. To display more than one graph select the Multiple
Graphs option and then choose the desired display option.
Pie Chart. Enter the data containing categories and frequencies in columns C1 and
C2. Or if the categories and frequencies are not given, then enter the categorical
data in column C1 as in Example B.9. From the command menu select Graph > Pie
Chart. Choose Chart Raw Data when each row in the column represents a single
observation or choose Chart Variables from a Table if the categories and frequencies
are given. Each slice in the pie is proportional to the number of occurrences
of a value in the column or the frequency of each category. Enter C1 in the box
next to Categorical Variables. A separate pie chart for each column is displayed
on the same graph. To display more than one graph select the Multiple Graphs
option and then choose the required display option. When category names exist
in one column and summary data exist in another column use the Chart Values
from a Table option. Enter the columns for Categorical Variables and Summary
Variables.
EXAMPLE B.9
Prepare a pie chart for the following categorical data:
Solution:
2 3 5 4 2 3 5 4
6 6 5 4 2 3 4 5
4 2 5 6 4 2 3 6
5 4 2 3 5 6
1. Enter the data in column C1 of the data window.
2. Select Graph from the command menu.
3. Click on Pie Chart in the pull-down menus available under the Graph
command menu.
4. Select Chart Raw Data from the options.
5. Enter C1 into the Categorical Variables box and click OK.
6. The Minitab output will appear in the graph window as shown in Figure B.13.
Continued