About multistage sampling

Multistage sampling-
Sampling:
It is the process of taking any portion of a population or universe as representative of that population or universe.One of the type of sampling is "Multi-Stage Sampling". Let's see some detail information about this type of sampling.
Multi-Stage Sampling:

Meaning:
In multi-stage sampling the material is regarded as made up of a number of first-stage units each of which is made up of second-stage units, and so on.
At the first stage of sampling, a number of first-stage units are selected; from each of the selected first-stage units, a number of second-stage units are then selected and so on.
An example of multi-stage sampling is where, firstly, electoral sub-divisions (clusters) are sampled from a city or state. Secondly, blocks of houses are selected from within the electoral sub-divisions and, thirdly, individual houses are selected from within the selected blocks of houses.
Charactaristics:
Multi-stage sampling does not require a complete list of members in the target population, which greatly reduces sample preparation cost.
Multistage sampling can involve more than one method or combined method of sampling, such as simple random, cluster or stratified sampling.
Multistage sampling uses a hierarchy of sampling units or clusters
Procedure:
Multi-stage sampling is like cluster sampling, but involves selecting a sample within each chosen cluster, rather than including all units in the cluster.
Thus, multi-stage sampling involves selecting a sample in at least two stages.
In the first stage, large groups or clusters are selected. These clusters are designed to contain more population units than are required for the final sample.
In the second stage, population units are chosen from selected clusters to derive a final sample. If more than two stages are used, the process of choosing population units within clusters continues until the final sample is achieved.
For Example:
A country may be considered as divided into a number of districts; each district into a number of villages; each village into. a number of farms. In multi-stage sampling a number of districts is selected in the first-stage within each such selected district a number of villages is selected in the second-stage, and from each selected village a number of farms is selected at the third-stage for enquiry. In the case of a crop-cutting investigation, the work may be carried further by the selection of fields from each selected farm and by plots within a field.
Advantages:
Multi-stage sampling are convenience, economic and efficient.
The technique is used frequently when a complete list of all members of the population does not exist.
It can dramatically reduce the cost of field operations.
Usually more accurate than cluster for same total size.Disadvantages:
The main disadvantage of multi-stage sampling is the same as for cluster sampling.
Lower accuracy due to higher sampling error.
Less accurate than SRS (Simple Random Samplig) of same size ·
Further analysis is difficult.
Activity:
You are employed by a market research organisation and have been asked to undertake a study across the whole of the British Isles to determine attitudes towards the National Lottery.What are the possible sampling frames for this study? You have been asked to interview 4,000 people in total. Consider what would happen if you undertook a simple random survey....... Of these 4,000 you might, for example, you have to interview 2 people in Shetland, 3 in the Outer Hebrides, a dozen scattered across the Borders, and so on. As this is uneconomic, both in terms of time and money, it would be considered more efficient to undertake a Multi-stage Cluster Sample. Think of some ways in which you could divide the country up into progressively smaller sections to undertake this type of sample.

References:

http://www.uic.edu/classes/socw/socw560/SAMPLING/sld001.htmhttp://www.abs.gov.au/Websitedbs/D3310116.NSF/4a255eef008309e44a255eef00061e57/116e0f93f17283eb4a2567ac00213517!OpenDocumenthttp://72.14.235.104/search?q=cache:9lyXaXyIaAAJ:unstats.un.org/unsd/publication/SeriesC/SeriesC_1_revised.pdf+advantages+of+multi+stage+sampling&hl=en&ct=clnk&cd=5&gl=inhttp://www.abs.gov.au/Websitedbs/D3310116.NSF/4a255eef008309e44a255eef00061e57/116e0f93f17283eb4a2567ac00213517!OpenDocumenthttp://www.cdc.gov/descd/MiniModules/pps/multistage_sampling.htmhttp://www.idrc.ca/en/ev-28312-201-1-DO_TOPIC.htmlhttp://had.co.nz/notes/surveys-expt/multistage-sampling.html
Presentated by:-
Vandana Jain (4)Nikita Munot (12)

About multistage sampling

Multistage sampling-
Sampling:
It is the process of taking any portion of a population or universe as representative of that population or universe.One of the type of sampling is "Multi-Stage Sampling". Let's see some detail information about this type of sampling.
Multi-Stage Sampling:

Meaning:
In multi-stage sampling the material is regarded as made up of a number of first-stage units each of which is made up of second-stage units, and so on.
At the first stage of sampling, a number of first-stage units are selected; from each of the selected first-stage units, a number of second-stage units are then selected and so on.
An example of multi-stage sampling is where, firstly, electoral sub-divisions (clusters) are sampled from a city or state. Secondly, blocks of houses are selected from within the electoral sub-divisions and, thirdly, individual houses are selected from within the selected blocks of houses.
Charactaristics:
Multi-stage sampling does not require a complete list of members in the target population, which greatly reduces sample preparation cost.
Multistage sampling can involve more than one method or combined method of sampling, such as simple random, cluster or stratified sampling.
Multistage sampling uses a hierarchy of sampling units or clusters
Procedure:
Multi-stage sampling is like cluster sampling, but involves selecting a sample within each chosen cluster, rather than including all units in the cluster.
Thus, multi-stage sampling involves selecting a sample in at least two stages.
In the first stage, large groups or clusters are selected. These clusters are designed to contain more population units than are required for the final sample.
In the second stage, population units are chosen from selected clusters to derive a final sample. If more than two stages are used, the process of choosing population units within clusters continues until the final sample is achieved.
For Example:
A country may be considered as divided into a number of districts; each district into a number of villages; each village into. a number of farms. In multi-stage sampling a number of districts is selected in the first-stage within each such selected district a number of villages is selected in the second-stage, and from each selected village a number of farms is selected at the third-stage for enquiry. In the case of a crop-cutting investigation, the work may be carried further by the selection of fields from each selected farm and by plots within a field.
Advantages:
Multi-stage sampling are convenience, economic and efficient.
The technique is used frequently when a complete list of all members of the population does not exist.
It can dramatically reduce the cost of field operations.
Usually more accurate than cluster for same total size.Disadvantages:
The main disadvantage of multi-stage sampling is the same as for cluster sampling.
Lower accuracy due to higher sampling error.
Less accurate than SRS (Simple Random Samplig) of same size ·
Further analysis is difficult.
Activity:
You are employed by a market research organisation and have been asked to undertake a study across the whole of the British Isles to determine attitudes towards the National Lottery.What are the possible sampling frames for this study? You have been asked to interview 4,000 people in total. Consider what would happen if you undertook a simple random survey....... Of these 4,000 you might, for example, you have to interview 2 people in Shetland, 3 in the Outer Hebrides, a dozen scattered across the Borders, and so on. As this is uneconomic, both in terms of time and money, it would be considered more efficient to undertake a Multi-stage Cluster Sample. Think of some ways in which you could divide the country up into progressively smaller sections to undertake this type of sample.

References:

http://www.uic.edu/classes/socw/socw560/SAMPLING/sld001.htmhttp://www.abs.gov.au/Websitedbs/D3310116.NSF/4a255eef008309e44a255eef00061e57/116e0f93f17283eb4a2567ac00213517!OpenDocumenthttp://72.14.235.104/search?q=cache:9lyXaXyIaAAJ:unstats.un.org/unsd/publication/SeriesC/SeriesC_1_revised.pdf+advantages+of+multi+stage+sampling&hl=en&ct=clnk&cd=5&gl=inhttp://www.abs.gov.au/Websitedbs/D3310116.NSF/4a255eef008309e44a255eef00061e57/116e0f93f17283eb4a2567ac00213517!OpenDocumenthttp://www.cdc.gov/descd/MiniModules/pps/multistage_sampling.htmhttp://www.idrc.ca/en/ev-28312-201-1-DO_TOPIC.htmlhttp://had.co.nz/notes/surveys-expt/multistage-sampling.html
Presentated by:-
Vandana Jain (4)Nikita Munot (12)

Difference between the two examples

Difference between first and second example
First example

• In this, the researcher is using a survey method to carry out the study.
• Here researcher is selecting the sample on a random basis i.e. out of 1000 primary school teachers in mumbai she is selecting 300 teachers randomly.
• To find out the oipinion of primary school teachers researcher might be using questionnair as a tool.
• For this survey method she requires only one group.

Second example

• In this researcher is using experimental method to carry out the study.
• Here researcher is selecting the sample randomly using a different method i.e. She lists everyone’s names on chits, and draws one chit out of the lot and writes that name under a column named linear CAI and non-linear CAI alternately and puts that chit aside.
• Hence, two groups of sample are selected for the study.
• Different treatment i.e linear CAI package to one group and non-linear CAI package to another group is given to check the effectiveness of the packages.

Simple random sampling v/s Convenience sampling

Difference between simple random sampling and convenience sampling

Simple random sampling-

1. In this type of sampling every individual from the entire population gets an equal chance of being selected.
2. Selection is free from biasness i.e. random selection is done.
3. Results of the study can be generalize to the entire population.
4. Sometimes the selected individual from the entire population may not be available/ accessible.
5. Also known as lottery method.

Convenience sampling-

1. In this type of sampling individual from the whole population do not get an equal chance of being selected.
2. Selection of sample involves biasness.
3. Results of the study cannot be generalize to the entire population.
4. Selected samples are easily available to the reasearcher.
5. Also known as accidental sampling or opportunity sampling.

Let's Communicate through Blog

Some quotes given by famous authors:

"Effective communication is 20% what you know and 80% how you feel about what you know."

by Jim Rohn

"Music is the greatest communication in the world. Even if people don't understand the language that you're singing in, they still know good music when they hear it."

by Lou Rawls

"Good communication is as stimulating as black coffee, and just as hard to sleep after."

by Anne Morrow Lindbergh

“The way we communicate with others and with ourselves ultimately determines the quality of our lives."

by Anthony Robbins

Criteria for sampling design

A good sample design requires the balancing of several important criteria:

1] Goal orientation-

• It consider both the selection processand the estimation process in terms of meeting research objectives.
• The sampling design should be based on the study's goals and objectives .
• Referring to the research objectives, tailored to the survey design and fitted to the survey conditions.

2] Measurability -

• The sampling design provides the data necessary for analysis (it enables valid inferences to be made about the population from the sample).
• It consider the ability to effectively quantify the variation in the sample statistics to provide a better handle indetermining characteristics of the population at large
• The aim of measurability is to understand the probability of sample selection, and to reduce unmeasurable biasesthrough better sample design.

3] Practicality -

• Practicality means being able to adapt to whatever irregularitiesoccur during the conduct of the survey
• The instructions should be simple, clear, practical and complete to accomplish the sample design.
• The actual activities of sampling have been identified and are feasible in the actual situation

4]Economy -

• Research objectives can be met with available resources (time, money, etc.)
• It concern with the fulfillment of survey objectives with minimum cost and effort and maximum statistical efficiency.
• Hence, Poorly designed surveys will increase the boredom factor for survey respondents

These four criteria frequently conflict, and survey researchers must balance and blend them to obtain a good sample design.

Examples

Examples:

1] If researcher wants to study the effect of multimedia packages on an academic achievement of post graduate sem I students of DET of S.N.D.T women's univ. Researcher can get the permission but may not be able to meet the participants as they would be busy in their final exams.

2] If researcher wants to find out an effect of Pogo channel program 'MAD' on the creative teaching skills of primary teachers. Researcher can get the permission but may not be able to meet the participants as they would be busy in the seting of final examination papers of the students.

3] Reseacher wants to study the variations in a section of economically backward people. in this case researcher may get the permission and can meet the participants also. But the problem may arise that the number of expertise in the statistical area are less.