1.4 Graphical Representations for One Categorical Variable
- Syllabus
- 2026
- Topic
- 1.4
- Level
- —
Learning objectives
1.4A—Construct categorical one-variable graphical representationsConstruct categorical one-variable graphical representations.• Bar charts, also called bar graphs, display frequencies (counts) or relative frequencies (proportions) for the categories of a single categorical variable. Each bar on a bar chart represents a category of the categorical variable of interest. The height or length of each bar corresponds to the frequency or relative frequency of the observational units in each category.• Pie charts are used to display frequencies (counts) or relative frequencies (proportions) for categorical data. Each slice on a pie chart represents a category of the categorical variable of interest. The area of each slice, as a fraction of the total area, corresponds to the relative frequency of observational units falling within each category. The sum of the slices’ areas together will equal 1, or 100% of the total area.1.4B—Justify a claim using categorical one-variable graphical representationsJustify a claim using categorical one-variable graphical representations.• Graphical representations of a categorical variable reveal information that can be used to justify claims about the variable in context.1.4C—Compare multiple categorical one-variable tabular and graphical representationsCompare multiple categorical one-variable tabular and graphical representations.• Frequency and relative frequency tables, bar charts, and pie charts can be used to compare two or more data sets in terms of the same categorical variable.
1.4.A—Construct categorical one-variable graphical representations
Construct categorical one-variable graphical representations.
- Bar charts, also called bar graphs, display frequencies (counts) or relative frequencies (proportions) for the categories of a single categorical variable. Each bar on a bar chart represents a category of the categorical variable of interest. The height or length of each bar corresponds to the frequency or relative frequency of the observational units in each category.
- Pie charts are used to display frequencies (counts) or relative frequencies (proportions) for categorical data. Each slice on a pie chart represents a category of the categorical variable of interest. The area of each slice, as a fraction of the total area, corresponds to the relative frequency of observational units falling within each category. The sum of the slices’ areas together will equal 1, or 100% of the total area.
1.4.B—Justify a claim using categorical one-variable graphical representations
Justify a claim using categorical one-variable graphical representations.
- Graphical representations of a categorical variable reveal information that can be used to justify claims about the variable in context.
1.4.C—Compare multiple categorical one-variable tabular and graphical representations
Compare multiple categorical one-variable tabular and graphical representations.
- Frequency and relative frequency tables, bar charts, and pie charts can be used to compare two or more data sets in terms of the same categorical variable.