Multistage sampling is a complex form of cluster sampling that involves multiple stages of sampling. It has advantages like being effective for primary data collection while being cost and time effective with flexibility. However, it can be subjective and findings may not fully represent the population. Purposive sampling selects elements based on the research purpose and objectives, being moderately cost effective but more biased. Snowball sampling is a non-probability technique where current subjects refer new subjects, allowing hidden populations to be reached cost effectively with little planning. However, bias from oversampling networks can occur and errors and representatives cannot be determined.

1. SOUMYA.S

2. MULTISTAGE SAMPLING

3.  Multistage sampling is a complex form of
cluster sampling.
 Contains two or more stages in sample
collection.

4. • ADVANTAGES

5.  Effective in primary data collection
 Cost effectiveness and time effectiveness
 High level of flexibility

6. DISADVANTAGES

7.  High level of subjectivity
 Research findings can never be 100%
representatives of population.
 The presence of group level information
is required

8. PURPOSIVE SAMPLING

9.  Elements are chosen from among the whole
population based on purpose of the study
 Main objective is that the researcher with
his good decision and appropriate policy
chooses those elements which are meant for
fulfilling the research objective

10. ADVANTAGES
 Moderately economic in terms of cost and
time because of small sample size
Closely related to the problem of study
 Useful for certain types of forecasting

11. DISADVANTAGES
 Useful only when the researcher has the
complete knowledge about the population
 More biased
 Impurities of the sample cannot be judged

12. SNOWBALL SAMPLING
 Non probability sampling technique
 Snowball sampling technique works as a
chaining system

13. TYPES OF SNOWBALL SAMPLING

14. LINEAR SNOWBALL SAMPLING
 Formation of a sample group starts with only
subject and subject provides only one referral.
 The referral is recruited into the sample group and
he or she also provides only one new referral.
 This pattern is continued until the sample group is
fully formed.

15. EXPONENTIAL NON DISCRIMINATIVE
SAMPLING
 The first subject recruited to the sample
group provides multiple referrals.
 Each new referral is explored until primary
data from sufficient amount of samples are
collected.

16. EXPONENTIAL DISCRIMINATIVE
SAMPLING
 Subjects give multiple referrals, however
only one new subject is recruited among
them
 The choice of a new subject is guided by the
aim and objectives of the study

17. ADVANTAGES
 Ability to recruit hidden populations.
 Possibility to collect primary data in cost
effective manner.
 A very little planning is required to staet
primary data collection.

18. DISADVANTAGES
 Over sampling of a particular network of
peers can lead to bias.
 It is not possible to determine sampling
errors.
 There is no guarantee about the
representatives of samples.