Here’s a Hand with Histograms

Hello again, data folks! I’m excited to introduce a type of chart that we haven’t yet touched upon in The Public Library Blueprints – the histogram! Histograms are a great tool for data analysis because they visualize the distribution of a single variable to help us understand the spread of the data. Because they also use bars to indicate values along a y-axis, histograms can be easily confused with bar charts. The big difference is that bar charts may present categorical data or two variables at once along the x- and y-axes, while histograms chart the distribution of one continuous variable. Statistics Canada provides a helpful refresher on the terms “variable,” “categorical,” and “continuous” if this terminology is tripping you up.

To demonstrate the difference in this post, we’ll use histograms to analyze the amount of time library outlets were open to the public in 2022. A bar chart could depict the average number of hours Colorado public libraries were open to the public by grouping libraries into distinct groups, such as by Legal Service Area (LSA) population, and then using the height of each bar to show the average number of hours each library group was open. However, we’re just going to focus on the distribution of average hours open per week, without additional variables, so it’s a histogram’s time to shine…

Continue reading this post on and check out more posts on research in a library context from Library Research Service.


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