Sampling.

Population:

It is the group of items, units or subjects which are under the reference of the study population is termed as universe by a number of statisticians or scientific population may consist of finite or an infinite number of units.

According to Kish, a population has to be defined in conjunction with the purpose of the study. Population is defined in terms of

Content (for example all persons).

Units (for example family units)

Extend (for example, the area covered)

Time (for example The calendar year)

Sample.

The sample is the units selected or taken from the population. It is a selection taken from a large group (the population) so that it can be examined to find out something about the large group is generally considered to be the sample. In many cases, it is practically not possible to include all units of the population investigation. Therefore, a few of the population units have to be selected as a representative of the whole population. The few selected unit/ a part of the population is called as the sample. However, two conditions are to be fulfilled for these few selected units to be a sample. The condition is as follows.

1. Each and every unit of the population must have non-zero probabilities for their inclusion in the sample selected.
2. The selection must be done according to accepted statistical procedure also known as sampling technique.

Sampling.

The process of selection of the sample from the population is called sampling.

Or it is the process of obtaining data as well as the information about an entire population by examination only a part of it. It is simply understood as the process through which sample is drawn from an entire population. In drawing samples, the following three criteria are to be included. They are as follows

1. For the purpose of the investigation.
2. Types of the sampling/sampling design to be used.
3. The size of the sample at each stage sampling.

The importance of sampling in research work.

it is the process of obtaining data as well as the information about an entire population by examination only a part of it. It is simply understood as the process through which sample is drawn from an entire population. It is important in research work for many purposes.

For the population consisting of a number of units , usually very large and sometimes infinitely many, it is practically not possible to include all units of the population for investigation. Therefore a few of the population units have to be selected as a representative of the world population. The few selected units of the population are called sample and the technique of drawing sample is called sampling. The sample should be truly representative of population characteristics without any bias so that it may result in valid and reliable conclusions.

Sampling is used in practice for a variety of importance such as.

1. Sampling becomes more logic when all the units of a domain are alike.
2. Sampling remains the only way when population contains infinitely many members.
3. It saves time, money as well as effort.
4. Sampling may enable more accurately measurement for a sample study as it is generally conducted by a trained and experienced investigation.
5. Sampling produce results at a relatively faster speed than a census method.
6. Sampling remains the only choice when the test involves the destruction of the item under study.
7. Sampling estimates the sampling errors and helps in obtaining the information concerning some characteristics of the population.

This is the purpose that research is important for many purposes.

The main objective of sampling.

The main objectives of sampling possess following characteristics as listed as below.

1. To produce results at a relatively faster speed.
2. To obtain information when population contain infinitely many members and the census is impossible.
3. To economise money, time, effort.
4. To obtain information of some characteristic of the population by estimating the sampling errors.
5. To make more logical when all the units of a domain are alike.

The steps to be followed in sampling.

The step to be followed in sampling is as follows.

1. Defining the population to be covered.
2. Defining sampling units.
3. Acquiring frame/list of the population elements

4. Deciding on the size of the sample.
5. Deciding on the type of the sample to be used.
6. Testing the reliability of the sample.

The importance of sampling.

1. There is the considerable saving in time and labour while using a sample.
2. Reduce cost of a survey.
3. It usually results in the reduction in cost in terms of money, and in terms of working hours.
4. Greater accuracy greater scope.

When the complete enumeration is not possible sampling is used . Sampling saves times and money and also it does not require a highly trained person for data collection.

5. If the population is too large , sampling is the best way to collect information.
6. If the testing is destructed, I,e the quality of the product can be determined only by destroying it in its process of testing.

Example Testing of the breaking strength of chalk.

7. When area of the survey is wide.

Sampling units.

The population units selected in simple is sampling units. Types of sampling units in socio- economic survey are.

1. Geographical units: Ecological regions, Districts, Cities, wards etc.
2. Structural units: A house, a flat etc.
3. Social group units: A family, a school, a club etc.

Limitation of sampling.

1. Proper care should be taken in the planning of sampling otherwise, results might be misleading.
2. Sampling also requires from trained and qualified people for planning and analysis.
3. If the universe ( Population units) are not enough census is better than sampling.

Reference.

Kerlinger, F.N. Foundation of Behavioural Research. New Delhi: Surjeet Publication, 2000.

Kothari, C.R. Research Methodology. India: Vishwa Prakashan, 1990.

Singh, M.L. and J.M Singh. Understanding Research Methodology. 1998.

Singh, Mrigendra Lal. Understanding Research Methodology. Nepal: National Book centre, 2013.