This document defines and classifies different types of variables that can be measured in research. It discusses numeric and categorical variables, experimental and non-experimental variables, and univariate, bivariate, and polyvariate variables. Numeric variables measure quantities and can be continuous or discrete. Categorical variables measure qualities or characteristics and can be ordinal, nominal, dichotomous, or polychotomous. Experimental variables include independent, dependent, and extraneous variables, while non-experimental variables involve predictor and criterion variables.

1. Variables
Practical Research 2 – Lecture 2
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2. Definition
 A variable is any factor or property that a
researcher measures, controls, and/or
manipulates.
 It is also the changing quantity or measure
of any factor, trait, or condition that can exist
in differing amounts or types.
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3. Definition
It is also a set of logical set of attributes,
characteristics, numbers, or quantities that
can be measured or counted.
It is also called a data item.
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4. Classification
1. Numeric
2. Categorical
3. Experimental
4. Non-experimental
5. Variables according to the number being
studied
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5. 1. Numeric Variables
 Variables with values that describe a
measurable numeric quantity and answer
the questions “how many” or “how much.”
 These values are considered quantitative
data.
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6. 1. Numeric Variables
a. Continuous variables (interval variables) –
assume any value between a certain set of
real numbers. The values depend on the
scale used.
time, age, temperature, height, weight
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7. 1. Numeric Variables
b. Discrete variables – assume any whole
value within the limits of the given
variables. The values depend on the scale
used.
number of children in the family
population of students
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8. 2. Categorical Variables
 variables with values that describe a
quality or characteristic of a data unit like
“what type” or “which category.”
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9. 2. Categorical Variables
a. Ordinal variables – these variables can
take a value which can be logically
ordered or ranked.
grades
sales
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10. 2. Categorical Variables
b. Nominal variables – these variables whose
values cannot be organized in a logical
sequence.
eye colors
languages
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11. 2. Categorical Variables
c. Dichotomous variables – these variables
represent only two categories.
gender (male and female)
answer (yes or no)
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12. 2. Categorical Variables
d. Polychotomous variables – these variables
represent many categories.
Educational attainment
Level of performance
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13. 3. Experimental Variables
a. Independent variables – these variables
are usually manipulated in an experiment.
It is also called manipulated or explanatory
variable.
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14. 3. Experimental Variables
b. Dependent variables – these variables are
usually affected by the manipulation of the
independent variables. They are also
called response or predicted variable.
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15. 3. Experimental Variables
c. Extraneous variables are also called
mediating or intervening variables.
These variables are already existing
during the conduct of an experiment and
could influence the result of the study.
They are known as covariate variables.
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16. 3. Experimental Variables
Title: An Experiment on the Methods of
Teaching and Language Achievement among
Elementary Pupils
IV – Method of Teaching
DV – Language Achievement
EV – Ventilation Facilities; Physical
Ambiance
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17. 3. Experimental Variables
Title: Use of Gardening Tools and Types of
Fertilizer: Their Effects on the Amount of
Harvest
IV – Use of Gardening tools; Type of
Fertilizer
DV – Amount of Harvest
EV – Humidity level; Types of Seeds/Plants
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18. 4. Non-experimental Variables
a. Predictor Variables – these variables changes
the other variable/s in a non-experimental
study.
b. Criterion Variables – these variables are
usually influenced by the predictor variables.
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19. 4. Non-experimental Variables
Title: Competencies of Teachers and
Students’ Behavior in Selected Private
Schools
PV – competencies of teachers
CV – students’ behavior
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20. 4. Non-experimental Variables
Title: Conduct of Guidance Counselling
Programs and Degree of Absenteeism and
Drop-Out Rate among Grade 11 Classes
PV – conduct of guidance counselling
program
CV – degree of absenteeism and drop-
out rate
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21. 5. Variables according to the number
being studied
a. Univariate – only one variable is being
studied.
b. Bivariate – two variables are being
studied.
c. Polyvariate – more than two variables are
being studied
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22. Assignment
1. Identify three general problems in your
community.
2. Specify the community.
3. List three specific problems under each
general problem.
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23. Assignment
General Problem: Behavior
Community: School
Specific Problem:
a. How students treat their classmates
b. How teachers address students’
misbehavior
c. How students behave towards success
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