SAMPLING &

NON SAMPLINGMETHODS

Statistics Topic-4

Sampling and sampling distribution.

1.Prababililty

sampling method

2.Non -Probability

sampling method

1.Simple random sampling.

2.Stratified random sampling

3.Systematic random sampling.

4.Multistage random sampling.

5.Cluster sampling.

1.Judgement sampling.

2.Quata sampling.

3.Convenience sampling.

4.Extensive sampling.

5.Purposive sampling.

6.Snow fall sampling.

1.Simple random sampling.

Each and every item of the universe has an equal chance of

being selected.

Lottery method-

Tables of random sampling.

Tippett's table.

2.Stratified random sampling.

This method is used when units of the universe are

heterogeneous .

steps-

1.Units of population are divided into different strata.

2.Then using random sampling , sample items are selected

form each strata.

For example-

1.Units of population are divided into different strata.

2.Choose equal proportion of the samples from each strata.

1000

students In

a

college.

200

Arts

students

300

Commerce

students

500

Science

students

10% sample is to be taken on the basis

of random sampling.

Then 20 students of arts, 30 commerce

and 50 students of science are selected

using random sampling.

This method assume equal proportion

of samples chosen from diff. strata.

So each units has equal chance of

being selected.

3.Systematic random sampling

in this method all the items are systematically arranged .

Then sample units are selected at equal intervals.

Numerically

If 10 students are to be selected from 100 .

First 10 would be selected at random.

Items can be arrange numerically , alphabetically, and

geographically,

Or. Every 10th item selected.

Or. Every 5th 15th 25th ..95th item selected. Systematically.

4.multi-stage random sampling.

When sampling procedure passes through many stages .

Firstly – entire population is divided into stages or sub-

stages.

From the each stage some units are selected on random

sampling basis.

To find out the literacy rate of U.P.

Example-

Some district will be selected randomly.

Select tehsil.

Villages or towns.

Wards

household

5.Cluster sampling.

In this method population is divided into many groups

called cluster.

Some clusters are selected on random basis.

The most common cluster used in research is geographical

cluster.

1.He can divide the entire population (population of Delhi) into diff.

strata(cities)

2.Then he selects a cluster on random basis.

2.Non -Probability sampling method

1.Judgement sampling.

In this method the selection of the sample items depends

on the judgment of the investigator.

Investigators exercise his judgment in the choice and

include those items in the samples which he thinks

correct.

2.Quata sampling

In this method , researcher chosen representative

individual from a group.

The investigators select the individuals ( sample items) to

collect information on their personal judgments within

the quotas.

Quota sampling is a type of judgment sampling.

3.Convenience sampling.

In this method investigator select the samples according

to his choice and convenience.

Eg- when a researcher collect the data regarding current

market situation.

He will choose the market which is near to him.

4.Extensive sampling.

In this method , sample size is taken almost big as the

population.

ie-90% of the population.

Due to large samples size this method has greater

accuracy.

5.Purposive sampling.

In this method researcher selects a sample based on their

knowledge about the study.

Researcher will chose the sample according to purpose

of the study.

Eg- if a reporter make a report regarding the football

word cup games by seeking the opinion of the public.

Then he will select those samples(individuals) who have

knowledge of football.

6.Snowball sampling

In this method , research participants recruit other

participants for a test or study.

This sampling method is used there are few samples and

difficult to find.

It is also known as chain-referral sampling.

Eg- data from drugs smuggling.

Prev. year ques.

SAMPLING &

NON SAMPLINGMETHODS

Statistics Topic-4