Week 2 of the Business Math Blog!
Charts are fun! They give people a way to see what information you have, and gives them a physical context to the data you’re showing them. There are three types of charts I’ll go over today, pie, bar, and plot. The one you’ll most commonly see is a pie chart. This is a good way to see relative percentages in a field, plus there’s some pretty colors too. Here’s an example of an ok but not fantastic pie chart:
This gives you some relative idea of what people like, but there’s no serious data displayed here.
This one is great! You can clearly see what the biggest sales are, the legend is labeled in full color and with the units the data represents, and the pie chart itself has distinct colors and slices so you can tell what’s where at a glance. Most of the data isn’t on the pie chart itself, but oftentimes you don’t want it there.
This one has solid data, but it’s less appealing. As mentioned, all of the data is on the chart, and between that and the rainbow effect that blends the slices together, it’s harder to follow this chart with your eyes. Add to that the small font, and your eyes begin to swim like it’s your fourth meeting before lunch.
The next type of chart I’ll talk about is bar charts:
Bar charts typically show individual values stacked on each other in neat piles, but they can also be used to compare percentage values over time.
This is an example of a bar chart not at its full potential. Sideways words really only work with a max of fifteen characters in a single line, and already it’s hard to decipher what this chart’s about. This is my blog, and I’m having trouble deciphering it. They’ve used commas instead of periods, which is only semi common for non-americans, the y-axis isn’t labeled at all, and no trend can be determined from this, making the data collected almost useless.
This chart is a perfect example of how percentage bar graphs should look! Percentages show data as part of a whole, and this clearly shows you how much each product contributes to the whole. The sections are labeled, the legend is clear and distinctly colored, and despite the art style being that of Windows ‘95, it’s overall aesthetically pleasing. Note that in this graph, they don’t include Saturday and Sunday, which one can infer means they don’t open. Instead of including the empty space (like the last one did), they don’t show the blank days. Does this skew the data? Nope! If there’s no sales, there’s no data to be skewed, so it’s all good!
Finally, plots and trendlines!
Plots are great for showing data changing over time, letting your eyes follow the ups and downs of the data as it goes throughout the years. Including multiple pieces of data (such as both sexes as the above chart does) lets people see the comparative value change as time goes on. The addition of the average rate makes it even easier to see the trend of the data as it moves. Speaking of “trends”…
Trendlines are a great addition to graphs, as they give a numerical idea of how the data is progressing. Even though the GDP line is going up and down, the trendline gives you a nice idea of how the economy progresses and where it’ll continue on to. For this reason, many trendline charts continue on after the data is completed to give people an idea of future data.
Here is a nicely done (and mildly alarming, given current events) trendline, this time with tolerances. Tolerances are a good way to declare to the reader, “hey, there’s some variation in this accuracy, but we know that it will follow this general line ±5%.” That way, you can show where the data is headed without getting thrown for a loop whenever there’s outlying pieces of data.
And that’s all the charts for today! As always, if you have any questions, comment and tag me!
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