Apple iWork '08 - Manual (Page 90)

90 Chapter 2 Getting Started with Numbers
Numbers creates a 2D column chart that plots the two selected values.
4 Click the Row button in the upper left.
Numbers assigns a
color to the table
column so you can
easily see how chart
elements map to
table data.
Click the Row button to
represent data in the chart by
row instead of by column.
The colors of the bars
match the table column
colors.