Page 157 - DMGT209_QUANTITATIVE_TECHNIQUES_II

Quantitative Techniques-II

Notes
Example: Suppose, we want to have 7500 households from all over the country. In such
a case, from the first stage, District, say 30 districts out of 600 are selected from all over the
country.
I Stage - Cities: Suppose 5 cities are selected out of each 30 districts; and
II Stage - Wards/Localities: say 10 wards/localities are selected from each city
III Stage - Households: 50 households are selected from each ward/locality.
In stage I, we can employ stratified sampling
In stage II, we can use cluster sampling
In stage III, we can have simple random sampling.

!
Caution The use of various methods shall give individually contribute towards accuracy,
cost, time, etc. This leads us to conclude that multistage sampling leads to saving of time,
labour and money. Apart from this wherever an appropriate frame is not available, the
use of multistage sampling has universal appeal.

Multi-stage Sampling

The name implies that sampling is done in several stages. This is used with stratified/cluster
designs.

An illustration of double sampling is as follows.
The management of a newly-opened club is solicits new membership. During the first rounds,
all corporate were sent details so that those who are interested may enroll. Having enrolled, the
second round concentrates on how many are interested to enroll for various entertainment
activities that club offers such as billiards, indoor sports, swimming, and gym etc. After obtaining
this information, you might stratify the interested respondents. This will also tell you the
reaction of new members to various activities. This technique is considered to be scientific, since
there is no possibility of ignoring the characteristics of the universe.

Task What are the advantages and disadvantages of multi-stage sampling? Enlist.

Area Sampling

This is a Probability sampling, a special form of cluster sampling.

Example: If someone wants to measure the sales of toffee in retail stores, one might
choose a city locality and then audit toffee sales in retail outlets in those localities.
The main problem in area sampling is the non-availability of lists of shops selling toffee in a
particular area. Therefore, it would be impossible to choose a probability sample from these
outlets directly. Thus, the first job is to choose a geographical area and then list out outlets
selling toffee. Then follows the probability sample for shops among the list prepared.

Example: You may like to choose shops which sell the brand—Cadbury dairy milk. The
disadvantage of the area sampling is that it is expensive and time-consuming.

152 LOVELY PROFESSIONAL UNIVERSITY