Data Analysis and Visualisation
Unit 9
Units 8 and 9 were all about visualising data in Excel using bar charts and histograms. While the charts themselves seem simple, the process of building them miticously helped correct bad habits in presenting and interpreting data.
Exercise 9.1 started by creating a percentage bar chart showing breakfast cereal brand preferences for Area 2. The aim was to mirror the chart from Area 1 and compare the two side by side. The key takeaway here was how visual tools can instantly reveal trends, for example, how one brand might be more popular in one area over another, even if the raw numbers didn’t look that different.
Exercise 9.2 built on that by combining both areas into a clustered column bar chart. This gave a clearer comparison between Area 1 and 2 in a single visual. The difference in preferences stood out much more sharply, showing the value of combining multiple variables into one visual without overcomplicating it.
Exercise 9.3 shifted focus to continuous data, introducing histograms. Here, we built a relative frequency histogram for weight loss under Diet B, matching the format used for Diet A. The process involved defining class intervals, calculating frequencies, and plotting them. It was more hands-on than a basic bar chart, but it gave a much better sense of the shape of the data, like whether it was symmetrical or skewed.
The rest of the unit also showed how to do the same in LibreOffice, but the key concepts remain the same: formatting, choosing the right chart type, etc… Overall, the unit reinforced how good visuals can summarise vasts amounts of data quickly and clearly, especially when comparing across groups or distributions.