# Representing a Health-related Variable

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

1. 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)