Population, Sample, and Sampling

C. Population, Sample, and Sampling

1. Population Educational Research is aimed at studying something which becomes a part of a number of people or individuals through studying the small part of the people or individuals. The large group of people or individual which has similar characteristics is called as population. Meanwhile, the small part of people or individuals with the same characteristics is a sample. Ary, 1985: 138) states that sample is defined as

a small group that is observed. He also adds that population is “all members of any well-defined class of people, events or objects”. The population of the research was the fifth grade students of elementary schools in Colomadu sub-district (Kecamatan) in the academic year of 2008/2009 which consists of twenty seven classes of twenty seven elementary schools.

2. Sample Sample is a part of population. According to Ary (1985: 138) sample is a small group that is observed. The researcher took two groups to be observed. The sample of the research was chosen from the fifth grade 2. Sample Sample is a part of population. According to Ary (1985: 138) sample is a small group that is observed. The researcher took two groups to be observed. The sample of the research was chosen from the fifth grade

3. Sampling Sampling technique is needed to decide a data source as a representation of population that will be observed. According to Vockell (1983: 103) sampling is the strategies which enable us to pick up a sub group from a larger group then use this subgroup as basis for making judgments about the larger group. The technique of sampling used in the research was purposive cluster random sampling. The cluster random sampling is taking sampling by randomization not to individual but to a group. Purposive refers to certain considerations. The considerations are they have similar English ability or starting point from the mean score of first semester. Another consideration is the fifth grade has the longest time in studying English among the first to fourth grade. Besides, the fifth grade is considered to be able to understand text better than the under grades. Operationally, the steps done in selecting sample were as follows :

a. Choosing two elementary schools in Colomadu sub-district. The sampling technique was randomization through lottery. From the a. Choosing two elementary schools in Colomadu sub-district. The sampling technique was randomization through lottery. From the

b. Deciding the class of the observation. The fifth grade was chosen because they had been taught English longer than the lower grades and they did not have to prepare for the National Examination. Besides, the students of those classes have similar ability or starting point in English lesson from the mean score of mid-semester.

c. The next step was dividing the classes based on their level of interest. Each class consists of forty students. Then, each class was divided into two groups, students who have high interest and students who have low interest. Therefore, there were four groups. Those groups can be seen in the following table:

Group Group Category and Methods

B 1 Students with high interest taught through group-

A 1 discussion using word wall.

B 2 Students with low interest taught through group- discussion using word wall.

B 1 Students with high interest taught through

A 2 expository teaching model.

B 2 Students with low interest taught through expository teaching model.

Table. 5. Table of Sample

Note:

A 1 : Group-Discussion using Word Wall

A 2 : Expository Teaching Model

B 1 : High interest

B 2 : Low interest