Is there a technique for making effective graphs?
Remember that a limited number of categories of comparison is necessary for both bar and pie charts. Too many categories make a chart difficult to interpret. If you find this to be the case, use the left query frame to limit the number of categories or values to a manageable number. A bar chart is useful for comparing several categories on a numerical scale, for example, the number of voyages on British and Dutch vessels in the period 1641-1700, when development of sugar colonies in the Caribbean began, or number of slaves embarked in different regions of Africa, or the average size (in tons) of United States and British ships. Number of voyages, slaves embarked, and tonnage are all numerical variables. Flag or nationality and region are categorical variables. Use of the query frame to limit categories represented in a bar or pie chart is a key to making effective use of the feature.
