RESEARCH APTITUDE

SAMPLING TECHNIQUES

PART-1

FOR:UGC- NET/JRF

PAPER-1

Meaning of Sample? “WHAT IS IT ?”

qA sample is a group of people objects or items taken from a larger population as a representative of the population.

q Process of making analysis using a partial part of the population is known as sampling.

qEg.In case of Maggie the samples were collected from some manufacturing units rather than the entire sample.

Importance of Sampling “WHY IS IT ?”

• It prevents wastage of time and money.• It reduces the chances of errors.• Sampling errors are less severe than that of non-sampling errors.• Sometimes the analysis requires sensitive elements such as blood,

hairs in such case using entire population is not possible.

“TELL ME MORE ?”

Sampling technique

s

Non-probability

Convenience Purposive Quota Snowball

Probability sampling

Simple Random Systematic Stratified Cluster

AreaMulti-stage

PROBABILITY VS NON- PROBABILITY SAMPLING

qProbability sampling is a sampling technique, in which the subjects of the population get an equal opportunity to be selected as a representative sample.

qNonprobability sampling is a method of sampling wherein, it is not known that which individual from the population will be selected as a sample and the samples shall be collected based on the discretion of the researcher rather than randomly.

CASE STUDY

q A research project requires the examination of the performance of students taking a particular training session. 2 students have used the below mentioned techniques. Kindly identify both the techniques.

Ø Student A chose 50 students randomly from the group of 200 students taking the training as respondents.

ØStudent B wanted to save time and efforts so he asked his friends(50) taking the training sessions to be the respondents.

Probability Sampling

• Samples are collected from the population based on the principle of randomization.• Each elements has an equal probability of being selected.• Eg- In the game of lottery the no for the Jackpot Prize is withdrawn

randomly where each no or element has an equal chance of being selected.

Simple Random Sampling

• Refers to a sampling technique where every element of the universe or population will have equal chance of being selected.• Eg-If there are 1000 students in an audience of a concert and 3

people are randomly called on the stage for an activity it is a case of random sampling.

Systematic Sampling

• The sampling technique where a systematic arrangement or a fixed interval is used to select a sample.• Also known as interval sampling• Eg- In a class of 50 students every 5th student sitting on a bench is

selected as a respondent for the research task. This leads to a selection based on a fixed interval basis.

Stratified Sampling

• The population shall be divided into homogenous groups, known as strata.• These homogenous groups are segregated or divided based on some

common characteristics from the population.• Eg. Dividing the population on the basis of different age groups,

income groups, religion is like grouping them into strata using stratified sampling.

Cluster Sampling

qThe population is divided into sub-populations randomly without any basis or characteristics.

qA random sample of clusters is selected from these sub-populations based on random sampling.

qThis is used when we want to examine the characteristics of a group rather than an individual element.• When sample elements are further selected from these sub-populations

it will be known as Multi-stage sampling.• When the clusters are made on the basis of the geographical area it is

known as area sampling.

CASE STUDYØXYZ ltd wish to examine the taste preferences of the consumers in the

whole of India, it divided the whole population into 4 groups. Further these groups were divided into sub-groups based on the region(East, west, north, south).The elements were selected randomly from these sub-groups created on the basis of region for the analysis and interpretation of results.• Cluster Sampling-The population is divided in 4 groups.• Area Sampling- The division of cluster groups into 4 Regions.• Multiple stage sampling-1st stage- Selection of clusters.

-2nd stage- Selection of elements from these clusters.

RESEARCH APTITUDE

SAMPLING TECHNIQUES

PART-2

FOR:UGC- NET/JRF

PAPER-1

Non-Probability Sampling

• In certain cases the researcher purposively chooses certain sample from the population then it is known as non-probability sampling.• In this case the elements do not have equal chances of getting

selected from the population.• Also known as Biased sampling technique.• Eg. Researcher wanted to interview certain Chartered accountants, he

asked one of his friends to take him to his Firm(chartered accountancy firm) to interview his colleagues.

Convenience Sampling

• When the samples are selected based on the convenience of the collection of the samples it is known as Convenience sampling.• It is based on the principle of ease of availability and selection.• Eg. Samples responses are taken from friends, relatives, neighbor as

per the convenience of the researcher.

Purposive Sampling

• When the researcher chooses the sample based on his own judgement and discretion it is known as purposive sampling.• It is also known as Judgement sampling.• In this case there can be a personal biasedness of the researcher.• Eg- A researcher may wish to interview them with whom he can get

favourable responses so as to get the desired outcome of the research.

Quota Sampling

• In this samples are collected from each strata based on the fixed quotas set for each of the elements.• It is used when we wish to include certain fixed proportion from

each elements.• Eg- A technology company wish to have data based on 30% quota

each from small, medium and large firms in order to conduct industry wise analysis of the demand for its product.

Snowball Sampling

• It refers to a technique of sampling where by the existing elements or respondents recruit future respondents for the study.• The researcher contacts few respondents and then these respondents

helps finding further respondents.• Since the sample expands like a rolling snowball, it refers to snowball

sampling.Eg- In case of sensitive issues such as drug addicts, AIDS patients etcsnowball sampling is the only way out to collect the samples.

Case Study on Sampling Techniques

q In order the conduct the general awareness quiz the students of a school were divided based on the basis of streams(Science, Commerce, Humanities)

q In order to conduct municipal elections the wards are segregated on the basis of region.

q What kind of technique shall be used for the game of “tambola”.q An automobile industry wish to research the demand for the new car

among different income classes and thus fixes 25% quota for respondents in each category.

q A researcher wishes to examine the case of drug addicts and wish to make a documentary on it.