3. At the end of the webinar session participants shall be able to :
1. Explain the different types of graphs for Qualitative data
2.Construct different types of graphs for Qualitative data.
4. Introduction:
• The graph is nothing but an organized representation of data. It helps us to
understand the data. The word data came from the Latin word Datum which
means “something given”
• After a research question is developed, data is being collected continuously
through observation. Then it is organized, summarized, classified, and then
represented graphically.
• In 1300’s ,graphs were not always used to present statistical findings. Graphs
were used to describe mathematical relationships but not for statistical purposes.
• The first significant statistical graphs were published much more recently,
usually credited to William Playfair (1759-1823), political economist and engineer
from Scotland.
• Origins of graphs in statistics – William Playfair (1759-1823)
5.
6.
7.
8. QUANTITATIVE
Qualitative data are
measures of 'types' and
may be represented by
a name, symbol, or a
number code.
Qualitative data are
data about categorical
variables (e.g. what
type).
Quantitative data are
measures of values or
counts and are
expressed as numbers.
Quantitative data are
data about numeric
variables (e.g. how
many; how much; or
how often)
Data collected about a numeric variable will always be
quantitative and data collected about a categorical variable will
always be qualitative. Therefore, you can identify the type of
data, prior to collection, based on whether the variable is numeric
or categorical.
9. For example, if data are collected on
annual income (quantitative),
occupation data (qualitative) could
also be gathered to get more detail on
the average annual income for each
type of occupation.
10. A bar graph is a type of chart in which each column (plotted either vertically or horizontally)
represents a categorical variable or a discrete ungrouped numeric variable.
Features of a bar chart:
In a bar chart, the bar height (if vertical) or length (if horizontal) shows the frequency for
each category or characteristic.
The distribution of the dataset is not important because the columns each represent an
individual category or characteristic rather than intervals for a continuous measurement.
Therefore, gaps are included between each bar and each bar can be arranged in any order
without affecting the data.
11. For example: If data had been
collected for 'country of birth' from a
sample of children, a bar chart could
be used to plot the data as 'country of
birth' is a categorical variable.
Reference:
https://www.abs.gov.au/websitedbs/D3310114.nsf/home/statistical+l
anguage+-+frequency+distribution
12. A line graph is a graphical display of
information that changes continuously
over time. Within a line graph, there
are various data points connected
together by a straight line that reveals
a continuous change in the values
represented by the data points.
Line graphs consist of two axes: x-axis
(horizontal) and y-axis (vertical). Each
axis represents a different data type,
and the points at which they intersect
is (0,0). The x-axis is the independent
axis because its values are not
dependent on anything measured.
13. A histogram is a graphical representation that
organizes a group of data points into user-
specified ranges. Similar in appearance to a
bar graph, the histogram condenses a data
series into an easily interpreted visual by taking
many data points and grouping them into
logical ranges or bins.
14. A Pie Chart is a type of graph that
displays data in a circular graph. The
pieces of the graph are proportional to
the fraction of the whole in each
category. In other words, each slice of
the pie is relative to the size of that
category in the group as a whole. The
entire “pie” represents 100 percent of a
whole, while the pie “slices” represent
portions of the whole.
Pie charts give you a snapshot of how
a group is broken down into smaller
pieces.
15. A picture graph, or pictograph, is a
graph used to display information that
uses images or symbols to represent
data.
What main features do pictograph
have? They must have a title. They
must have a key to show what each
symbol or picture means. Each picture
must be of identical size.
16. A scatter plot is a type of plot or
mathematical diagram using Cartesian
coordinates to display values for
typically two variables for a set of data.
If the points are coded, one additional
variable can be displayed
Can scatter plot be used for qualitative
data?
Data do not need to be quantitative to
be plotted in a scatterplot. Instead,
data on the x-axis could be qualitative,
categorical, or ordinal. ... Another use
of scatterplots is to assess statistical
assumptions for linear models
17. A Pareto Chart is a combination of a bar
graph and a line graph. Notice the
presence of both bars and a line on the
Pareto Chart.
Each bar usually represents a type of
defect or problem. The height of the bar
represents any important unit of measure
— often the frequency of occurrence or
cost.
The bars are presented in descending
order (from tallest to shortest). Therefore,
you can see which defects are more
frequent at a glance.
The line represents the cumulative
percentage of defects.
