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In bar graphs, the order of the categories does
not usually matter. However, bar graphs that
have categories arranged in decreasing order
of frequency help prioritize categories for
decision-making purposes in areas such as
quality control, human resources, and
marketing.
Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
Histogram
✦
It is constructed by drawing rectangles for each class of
data. The height of each rectangle is the frequency or
relative frequency of the class. The width of each rectangle
is the same and the rectangles touch each other.
✦
It is a graph used to present quantitative data, is similar to
the bar graph.
✦
It is use to organize continuous data.
stat500/lesson/1/1.6/1.6.2

Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
✦
It is a circle divided into sectors. Each sector represents a
category of data.The area of each sector is proportional to
the frequency of the category.
✦
Pie charts are typically used to present the relative
frequency of qualitative data. Inmost cases the data are
nominal, but ordinal data can also be displayed in a pie
chart.
Pie Chart
Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
When should a bar graph or a
pie chart be used?
✦
Pie charts are useful for
showing the
division of all possible values of a
qualitative variable into its parts
.
✦
Bar graphs are useful when we want to
compare the different parts
, not necessarily
the parts to the whole.
Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
✦
A graph that shows information that is
connected in some way (such as change over
time)
✦
Line segments are then drawn connecting the
points. It is use to organize continuous data.
✦
Very useful in identifying trends in the data
over time.
Line Graph

Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
The simplest of line graphs is the single line graph, so
called because it displays information concerning one
variable only, in terms of its frequencies.
Example:
Simple Line Graph
Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
Multiple line graphs illustrate information on
several variables so that comparison is possible
between them.
Multiple Line Graph
Example:
Polytechnic University of the Philippines
College of Science
Department of Mathematics and Statistics
Guidelines for Constructing
Good Graphics
✦
Title and label the graphic axes clearly,
providing explanations if needed. Include units
of measurement and a data source when
appropriate.