Bar Charts of Sums & Means
Lesson
You know by now that a bar chart of values can display the values of a quantitative attribute for different categories of a categorical attribute as bars. A bar chart of sums extends the notion of displaying the values of a quantitative attribute for different categories by stacking the categories end to end and aggregating the values for each category. You can create a variety of bar charts of sums in Tuva. Bar Chart of Sums with a Single Quantitative Attribute: You can create the most basic bar chart of sums in Tuva by dragging and dropping a quantitative attribute on the x- or y-axis and choosing the bar chart of sums from the toolbar. ![]700 The bar chart of sums will look like this: ![]700 Note that the bar annotation shows the sum of all the values of the quantitative attribute plotted on the axis. You can also select individual cases in the bar chart. Bar Chart of Sums with a Quantitative and a Categorical Attribute: The bar chart of sums can also be used to display the sum of the values of a quantitative attribute for each category of a categorical attribute. The steps for creating a bar chart of sums using a combination of a quantitative and a categorical attribute are shown below: Step 1: Drag and drop a quantitative attribute on any one of the axes and choose :ti[bar-chart-of-sums] from the toolbar to create a basic bar chart. Step 2: Click on a categorical attribute or drag and drop it in the Legend Area. ![]700 The bar chart of sums now displays the sum of the values of the quantitative attribute for each of the categories of the categorical attribute you applied to the legend. ![]700 Bar Chart of Sums with a Quantitative Attribute and Two Categorical Attributes: When you create a bar chart of sums with a quantitative attribute and two categorical attributes, you are able to display the sum of the values of a quantitative attribute for each category of a categorical attribute across the categories of the second categorical attribute. Here are the steps to creating such a chart: Step 1: Create a bar chart of sums with a quantitative attribute on any one of the axes and a categorical attribute in the Legend area. Step 2: Next, drag and drop a categorical attribute on the empty axis. ![]700 Step 3: Your finished graph will look like this: ![]700 Bar Chart of Means: Tuva offers you yet another type of bar chart, that is, the bar chart of means. The type of bar chart allows you to visualize the mean of a quantitative attribute. To create a bar chart of means, you need to drag and drop a quantitative attribute on any one of the axes and choose :ti[bar-chart-of-means] from the toolbar. ![]700 Your finished graph will look like this: ![]700 You can also compare the means across the categories of a categorical attribute by simply dragging and dropping a categorical attribute on the empty axis. ![]700 In the interactive tutorial that follows, you will explore the Dinosaurs dataset and create your own bar charts of sums and means on Tuva. ![]720
Topics and standards: Bar Chart of Sums, Bar Chart of Means, Tutorial