In descriptive statistics there is substantial focus on how data is presented in visual form, hence, the many forms of graphical presentation that are used. For example, many data software packages now include: frequency and percentage tables, bar charts, histograms, line graphs, pie charts, high and low charts, scatterplots, stem and leaf displays, and boxplots.

1. Descriptive
Statistics
Dr Ryan Thomas Williams

2. Data analysis
• Descriptive statistics or inferential statistics
• ‘A useful means of classifying a different method of social
research than qualitative analysis.’ (Byman 2008)
• Looking to test a hypothesis - support or reject what you
already presume to know about the phenomena.

3. Descriptive statistics
• In descriptive statistics there is substantial focus on how data is
presented in visual form, hence, the many forms of graphical
presentation that are used. For example, many data software
packages now include: frequency and percentage tables, bar charts,
histograms, line graphs, pie charts, high and low charts, scatterplots,
stem and leaf displays, and boxplots.

4. Guidelines
• There are some general guidelines with regards to presenting and these are
as follows:
• Bar charts for presenting categorical and discrete data,
• 3D bar charts and histograms are often unnecessary unless they add value,
• Histograms for presenting continuous data,
• Line graphs for presenting trends,
• Pie charts are useful for showing proportions,
• Scatterplots are useful for showing relationships, and
• Boxplots are useful for the distribution of variables

5. Bar charts
• Bar chart: an illustration of qualitative data representing a variable’s
categories on the x- axis as independent vertical bars and simple
frequencies on the y-axis
0
10
20
30
40
50
60
70
80
90
100
A B C D E F G H I
Sales
Teams
Sales Performance

6. Pie chart
• Pie chart: an illustration of nominal data representing a variable’s
categories as portions of a circle (or slices of a pie)
13%
14%
13%
11%
13%
13%
9%
6%
8%
Sales Performance
A
B
C
D
E
F
G
H
I

7. Histograms
• Histogram: an illustration of quantitative data representing the range
of a variable’s values on the x-axis and frequencies of those ranges on
the y-axis, with no gaps between bars

8. Frequency polygon
• Frequency polygon: an illustration of quantitative data representing
bins as segments on a line graph
0
2
4
6
8
10
12
38 49.5 59 68 77 86 95 100
Frequency
Scores (/100)
Customer Satisfaction

9. Scatterplots
• Scatterplots: an illustration of qualitative and/or quantitative data that places
one variable of interest on the x-axis and a second variable of interest on the y-
axis. This allows the viewer to see the relationship between the two variables.
75
275
475
675
875
1075
95 195 295 395 495 595 695 795 895 995
Number
of
Sales
2022
Number of Sales 2021
Sales 2021 vs 2022

10. Boxplots

11. Central tendencies
• Central tendencies measure the mode, mean and median of a set of
data, and they too have their own general guidelines
• If scores are widely dispersed around the mean, then Standard
Deviation (SD) can be used to calculate the average distance a score
is from the mean. SD is calculated as:

12. Example of SD- σ
• The sales director is
analysing the results of a
recent customer
satisfaction survey that
ranks the service from 1-
10.
Customer satisfaction
6.9
8.0
4.9
9.3
7.8
3.9
5.0
1.9
8.2
2.9
Mean 5.87
SD 2.50