Give one example of health-related data (a variable) that can be represented by a pie
chart. Do the same for a bar chart and a histogram. Explain why each data example you
selected (there will be a total of three different variables) is well represented by the
corresponding graph.
Representing a Health-related Variable
In order to represent health-related data correctly, the raw data is first arranged in a
table. This is the data used to create graphs, which are an effective way of representing data.
Bar chart, histogram, and pie chart are the basic types of graphs for health-related variables.
Pie charts are very effective for representation of qualitative data, one that occurs with
relative frequency. A pie chart is a circle divided into sections, with each section representing
frequency proportionally. (Sullivan, 2013) A health-related variable that would fit in such a
representation is the percentage of malaria misdiagnosis that caused deaths of children in
- This form of presentation is relevant because the aim is to show how the respective
percentages of the variables, not their frequencies.
pneumonia,64%
asthma,25%
typhoid,11%
Misdiagnosis of Malaria in 2012
Health-Related Variables 2
Fig 1: Sample Pie Chart: Misdiagnosis of Malaria in 2012
Then there is a histogram, which applies for quantitative data. This representation is
shown by rectangles whose height represents relative frequency of the data. (Sullivan, 2013)
Data that fits a histogram representation is the frequency or number of malarial misdiagnosis
in different age groups of children. Examples of such age groups are 0-4 years, 5-9 years, 10-
14 years, and so on. This data occurs in intervals with a frequency in each case, making a
histogram the most appropriate data presentation method.
200
150
100
50 cases
0-4 years 5-9 10-14
Fig 2: Sample Histogram: Frequency Of Malarial Misdiagnosis in 2012
Health-related variables might also appear in the form of a bar chart. Similar to a pie
chart, a bar chart is suitable for qualitative representation of data. A bar chart consists of
several data categories on one axis and their relative frequencies on the other axis. Each of
these categories has its own rectangle. (Sullivan, 2013) A good example of data that might be
Health-Related Variables 3
displayed using a bar chart is the number of misdiagnosis that caused children deaths in
January, June, and December 2012. Here, the emphasis is on nominal level, thus histogram
does not apply.
JanuaryJuneDecember
0
10
20
30
40
50
60
Pneumonia
Asthma
Typhoid
Fig 3: Sample Bar Chart
Health-Related Variables 4
Reference(s)
Sullivan, M. (2013). Statistics: Informed Decisions Using Data. (Third Ed.pp. 65-120).
Prentice Hall PTR. (Sullivan, 2013)