RESEARCH ON ELT I

Lecture II

Rida Wahyuningrum

English Department

Wijaya Kusuma University, Surabaya

By the end of this course, you will be

able to :

mention the definition of

population and sampling,

and types of sampling

techniques

What is

Population?

A research population is generally a large

collection of individuals or objects that is

the main focus of a scientific query.

It is also defined as a well-defined

collection of individuals or objects

known to have similar characteristics.

All individuals or objects within a

certain population usually have a

common, binding characteristic or

trait.

In short, population does not

only cover people but also

the other objects. It is not just

about the number of the

object/subject being studied,

but rather covering the

characteristic/nature they

have as well.

However, due to the large

sizes of populations,

researchers often cannot

test every individual in the

population because it is too

expensive and time-

consuming. This is the

reason why researchers

rely on sampling

techniques.

What is

Sampling

Technique?

Sampling or sampling

technique is the process of

selecting a group of subjects for

a study in such a way

that the individuals represent

the larger group from which

they were selected.(L. R. Gay, 1987:01)

This representative portion of a

population is called a sample.(Ary et. al., 1987:125)

A sample-based research is

applicable when the subject of

the study is claimed to be

homogenous.

Sample-based research is more

advantegous rather than that of

population-based one because of the

following reasons :

1. You can save time, cost, and energy for

the subject of the study is relatively

small in number.

2. You might not miss important details.

3. You may not experience fatique in terms

of note taking and analysis.

TYPES OF

SAMPLING

RANDOM NON RANDOM

every individual in the population have equal chance of being selected as a subject for the

research

members of the population do not have equal chance of being selected

The advantage of using probability sampling is the accuracy of the statistical method after the experiment. It can also be used to estimate the population parameters since it is representative of the entire population. It is also a reliable method to eliminate sampling bias.

This sampling method is usually employed in studies that are not interested in the parameters of the entire population. Some researchers prefer this sampling technique because it is cheap, quick and easy.

RANDOM SAMPLING

SIMPLE RANDOM SAMPLING

STRATIFIED RANDOM SAMPLING

CLUSTER RANDOM SAMPLING

SYSTEMATIC RANDOM SAMPLING

AREA RANDOM SAMPLING

NON RANDOM SAMPLING

CONVENIENCE SAMPLING

PURPOSIVE SAMPLING

SNOW-BALL SAMPLING

The detailed

explanation about

sampling techniques

is provided in M-

Word file