7 Choosing the best way to present your data

You have looked at several ways of presenting data, but how do you select the best one to use?

• Tables can be used to organise complicated data. They are useful if you need to look up information.
• Pictograms are a good way of displaying data in an accessible, ‘fun’ way. They are good at showing simple data. However, a picture key can make it difficult to be accurate when the key is used to represent larger values: if the following figure represents 50 ...
  

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  An illustration of bicycle.

  ... what does this figure represent?
  

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  An illustration of bicycle, with the front of the bicycle cropped off.

  It could be 35, but it could also be 34, 36 or 37, etc.
• Pie charts show the breakdown of different parts of a whole data set. Each segment represents a percentage or proportion of the whole amount. Pie charts are good for showing which parts take up the largest or smallest part of the pie. They are not so good when there isn’t much difference between the values, as it can be difficult to see small variations.
• Bar charts are great for comparing discrete data.
• Line graphs are often used to show changes or trends in data over time.

Activity 14: Choosing how to display data

Select the best way to display the following sets of data:

1. The number of visitors to an exhibition over a day.
2. The breakdown of each food group that makes up a healthy diet.
3. The profit made by different branches of a shop over three months.
4. The number of patients who missed GP appointments over six months in a GP surgery waiting room.

Answer

1. A line graph would be suitable because it would show the change in visitor numbers over the day.

Figure 19 St David’s Hall line graph

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An illustration of a line graph showing how many visitors come to St David’s Hall on an open day.

Figure 19 St David’s Hall line graph

2. A pie chart would show the proportion of each food group compared to the others.

Figure 20 Healthy diet pie chart

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An illustration of a pie chart showing food groups in a healthy diet.

Figure 20 Healthy diet pie chart

3. A bar chart would allow comparison of profits at the different branches.

Figure 21 Cambria Retail bar chart

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An illustration of a bar chart showing quarterly profits at various branches of Cambria Retail.

Figure 21 Cambria Retail bar chart

4. A pictogram would make the results accessible and easy to read.

Figure 22 Missed appointments pictogram

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An illustration of a pictogram showing how many appointments have been missed at a clinic.

Figure 22 Missed appointments pictogram