# Bars on a graph

In Minitab, the height of each bar on a graph represents a statistic for a category (categorical data) or interval (continuous data).

Histograms, bar charts, and Pareto charts are examples of graphs that have bars by default.

### Graphs that display bars as an option

You can display bars in marginal plots, interval plots, and individual value plots

## Modify the colors of bars on a graph

Suppose your bar chart summarizes the following data:

C1 C2 C3 C4
Operator Machine Data Colors
1 1 6 4
2 1 7 4
3 1 8 4
4 1 9 3
1 2 6 2
2 2 7 2
3 2 7 2
4 2 7 2

### Change the color of all bars or an individual bar

1. Create a bar chart of the data in the example worksheet:
1. Choose Graph > Bar Chart.
2. From the Bars represent, choose Values from a table.
3. Under One column of values, choose Cluster. Click OK.
4. Under Graph variables, enter Data. Under Categorical variables for grouping (1-4, outermost first), enter Machine and Operator.
5. Click OK
2. Double-click the graph.
3. Select the bar or bars that you would like to change. Click a bar one time to select all bars. Click a second time to select an individual bar.
4. Double-click a selected bar.
5. On the Attributes tab, under Fill Pattern, choose Custom.
6. From Background color, choose the color.
7. Click OK.

### Create a graph with each cluster of bars a different color

1. Choose Graph > Bar Chart.
2. From the Bars represent, choose Values from a table.
3. Under One column of values, choose Cluster. Click OK.
4. Under Graph variables, enter Data. Under Categorical variables for grouping (1-4, outermost first), enter Machine and Operator.
5. Click Data View.
6. In Categorical variables for attribute assignment, enter Machine.
7. Click OK in each dialog box.

### Use an attribute column to specify colors

1. Choose Graph > Bar Chart.
2. From Bars represent, choose Values from a table.
3. Under One column of values, choose Cluster. Click OK.
4. In Graph variables, enter Data and in Categorical variables for grouping (1-4, outermost first), enter Machine Operator Colors.
5. Click Data View
6. In Categorical variables for attribute assignment, enter Colors.
7. Click OK in each dialog box.
8. Double-click the graph.
9. Double-click the x-axis of the bar chart. On the Scale tab, under Space Between Scale Categories, deselect Gap within clusters and enter -1.
10. Deselect Gap between clusters and enter 0.
11. Click the Show tab. In Show Labels By Scale Level, deselect Tick Labels for Colors. Click OK in each dialog box.

### Use an attribute column to specify the colors (with session commands)

1. Click View > View Command Line/History.
2. In the Command Line pane, enter the following command lines:
``````Chart Sum(Data)*Machine;
Group Operator;
Bar;
Color Colors.``````
3. Click Run.

## Change the base position of bars

The base position is a value from which the bars originate. Graphed values greater than the base position project up from the line; graphed values less than the base position project down from the line. You can change the base position, for example, to show distance from a target value.

1. Double-click the graph.
2. Double-click a bar.
3. On the Box Options tab, under Base Position, click Custom and enter a y-scale value for the base position.
4. Click OK.

### Example of changing the base position of bars

Suppose each person on your sales team has a goal of \$12,000 for a month. The base position 0 makes it easy to compare total sales. To emphasize the relationships to the target value of \$12,000 (12 on the y-scale), you set the base for the bars to 12 and draw a reference line there. Now, you can see that Steve's totals are below the goal, Mary's are slightly above, and Roberto and Bill's are the highest.