Posted by: tonyteaching | May 25, 2009

Types of Variables

Basically, “research” is one of human activities to disclose ‘knowledge gap’ to increase the knowledge (understanding) about the world phenomena.

Since we have many limitations in ability to investigate (e.g. we have limitation in time, money, researcher) then in most cases a researcher can not investigate a whole population of the research object. Here, generalization or conclusion then is withdrawn which is just based on the sample.

Some terms in Research:

——————————

* Unit:

a single object upon which the study is carried out.

Examples of unit are a student, a patient, a sample of water, a book, or a mark.

* Population:

an entire collection of units (or the entire group) which we wish to describe or draw conclusions about.

* Sample:

a subset of units selected from the population which is intended to represent the population.

* Variable or Atribute:

one of characteristics of units which differentiate among every unit

For example:

Student ID Name Gender GPA

__________________________

123 Tony M 6.11

124 John M 5.25

125 Jhine F 7.00

Here,

the Population : may be all students in comp1301

the unit: student

the sample: are these three students

the variables: student ID, name, gender, and GPA

the value of variable gender can be M or F

—————————————————-

The types of variables

The characteristics can be measured using word (it is called “Category” variables) or using number (it is called “Quantity” variables).

There are 2 types of Category variables:

* “Ordinal” variable : if values of the variable (word) can be ordered.

Examples of Ordinal variables are

education level (the values can be primary school, secondary school, university)

level of agreement (strongly agree, agree, neutral, disagree, strongly disagree)

* “Nominal” variable : if values of the variable (word) can not be ordered.

Examples of Ordinal variables are

Countries origin (the values can be Australia, Indonesia, …)

Gender (the values can be Male, Female)

Eye color (blue, brown, black)

There are 2 types of Quantity variables:

– “Discrete” (counting) variable : if values of the variable (number) must be whole number

Examples :

number of kids (the values can be 1,2,3,4. It is impossible 1.5 or 2.25)

-“Continuous” (measuring) variable : if values of the variable (number) can be fraction numbers.

Examples :

weight (the values can 50.25 kg or 75.5 kg)


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