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Skip to 0 minutes and 0 seconds[music playing] welcome back to gmba 71 202. Data analytics for decision making, and in this module 1b we're really looking at graphs, graphical analysis. And we're going to consider pie and bar charts, histogram, line plot, scatter plot and some ideas around what makes a good graph in general. Before in part c and d then we'll look at descriptive methods and ethics but now this module is all about graphs so let's get into it. Firstly pie and bar charts um very popular well-known, easy to do in excel and they're appropriate when you have data that can be naturally categorised in a meaningful manner. So thinking about qualitative variables for example, or key groupings.

Skip to 1 minute and 18 secondsClassic example might be budget so you know the amount of budget could be divided into how much for research and development, how much for marketing, how much for general operations, administration etc. We have key meaningful categories. But we're talking about graphs so let's have a look at one rather than see text.

Skip to 1 minute and 45 secondsWell here's an example of a pie chart for example we have a, fund a mutual fund, Adrian Fund and this is 2011 performance and this is a pie chart for the investment strategy, so our money gets divided up into 10% cash 20% international stocks 30% domestic and or 30% domestic bonds, 40% domestic stocks so it's a nice way to sort of visually see the components and how the different investments. So that would be a pie chart the same information could be displayed on a bar chart, and here we have labels for each of the columns. What you might like to do on a bar chart depending on what you're trying to highlight.

Skip to 2 minutes and 34 secondsIs order them so that you can see okay domestic stocks, then bonds then, international stocks, then cash. It's pretty easy with four columns but if you had some more columns it might be a bit harder to see the ordering unless you order it for the reader. Now notice the some key things here I have access labels ,so proportion of total investment I have on the axis label, and I have a nice chart title ,and see those also the labels on the bars forty percent, thirty percent, twenty percent, ten percent you could have those or sometimes you don't have those. And in this example notice i've also changed the axis, it's the amount invested.

Skip to 3 minutes and 18 secondsBut notice it takes a little bit longer to say international stocks how much? I've got to go across there oh it's 40 million dollars whereas if it had it just above, like before, when we go back we had that information you know written above the bars it was a bit faster again it depends on what you're trying to highlight to the reader. If the actual value is important you might like to include that bu,t if it's more about comparing between and the actual values it's just relative values are more important maybe you don't. But again information to think about.

Skip to 3 minutes and 55 secondsDo I display that how don't I, that's key information here but i think hopefully we're pretty safe with, and pretty familiar with pie charts and bar charts so we're going through those fairly quickly. So just to recap pie chart the size of each slice of the pie is proportional to the size of the category it represents, so bigger slices you know, bigger chunks, bigger amounts, bigger shares. Now that highlights the proportion of the whole ,naturally, you can see sort of how much of the the pie or the pizza if you like to think about it. That you are contributing to for example again if it was that budget idea, how much of the overall company's budget is your division taking?

Skip to 4 minutes and 38 secondsAnd you can clearly see that bar chart, it uses bars instead of slices and it's a bit easier to compare categories to see which one is bigger. And I'm going to go back here just to highlight that to you. So let's just go back for a moment now have a look at this without the text. It takes a while to determine that the blue category is bigger than the red, just looking at the pie you're like yeah, yeah it is a bit bigger, but immediately when you see it on a bar chart you can see domestic stocks bigger than domestic bonds.

Skip to 5 minutes and 21 seconds Even when you don't have the amounts there it's clearly easy to compare the different categories so that's something to consider there

Pie Charts and Bar Charts

Do we want to know how different products contribute to profit? Then a pie chart might be the answer. Do we want to know how many sales we had for different salespersons? Then a bar chart might be the answer.

These are just two easy examples of when a pie or bar chart can provide a quick and effective description of your data. In this video, Adrian talks about these types of charts and how they can be used. You’ve probably seen them before, though, as there are so many questions they are helpful for.

Let’s discuss

In the comments below, share an example of when you may use a pie chart vs a bar graph in your own work or study.

Soon we’ll step through how we made these charts in Microsoft Excel. For now, if you are comfortable with these two charts, let’s move on to start learning about Histograms.

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This video is from the free online course:

Data Analytics for Decision Making: An Introduction to Using Excel

Bond University