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Choosing a sampling method

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❶Some polls go even farther and have a machine conduct the interview itself rather than just dialing the number! Probability Sampling — Uses randomization and takes steps to ensure all members of a population have a chance of being selected.




Examples of Data Collection Methods — Following is a link to a chart of data collection methods that examines types of data collection, advantages and challenges.

Qualitative and Quantitative Data Collection Methods - The link below provides specific example of instruments and methods used to collect quantitative data.

Sampling and Measurement - The link below defines sampling and discusses types of probability and nonprobability sampling. Principles of Sociological Inquiry — Qualitative and Quantitative Methods — The following resources provides a discussion of sampling methods and provides examples. This pin will expire , on Change. This pin never expires. Select an expiration date. About Us Contact Us. Search Community Search Community. Sampling Methods Sampling and types of sampling methods commonly used in quantitative research are discussed in the following module.

Define sampling and randomization. Explain probability and non-probability sampling and describes the different types of each. There are several variations on this type of sampling and following is a list of ways probability sampling may occur: Random sampling — every member has an equal chance Stratified sampling — population divided into subgroups strata and members are randomly selected from each group Systematic sampling — uses a specific system to select members such as every 10 th person on an alphabetized list Cluster random sampling — divides the population into clusters, clusters are randomly selected and all members of the cluster selected are sampled Multi-stage random sampling — a combination of one or more of the above methods Non-probability Sampling — Does not rely on the use of randomization techniques to select members.

The different types of non-probability sampling are as follows: Method Best when Selective sampling gut feel Focus is needed in particular group, location, subject, etc. Theoretical sampling testing a theory Theories are emerging and focused sampling may help clarify these. Home Top Menu Quick Links. Probability methods This is the best overall group of methods to use as you can subsequently use the most powerful statistical analyses on the results.

When population groups are separated and access to all is difficult, eg. Proportionate quota sampling in proportion to population sub-groups. You know the population distribution across groups, and when normal sampling may not give enough in minority groups.

Non-proportionate quota sampling minimum number from each sub-group. Modal instance sampling focus on 'typical' people. When sought 'typical' opinion may get lost in a wider study, and when you are able to identify the 'typical' group. You are specifically seeking differences, eg. Selective sampling gut feel. Such " robo call polls " can be very biased because they have extremely low response rates most people don't like speaking to a machine and because federal law prevents such calls to cell phones.

Since the people who have landline phone service tend to be older than people who have cell phone service only, another potential source of bias is introduced. National polling organizations that use random digit dialing in conducting interviewer based polls are very careful to match the number of landline versus cell phones to the population they are trying to survey. The following sampling methods that are listed in your text are types of non-probability sampling that should be avoided:.

Since such non-probability sampling methods are based on human choice rather than random selection, statistical theory cannot explain how they might behave and potential sources of bias are rampant.

In your textbook, the two types of non-probability samples listed above are called "sampling disasters. The article provides great insight into how major polls are conducted. When you are finished reading this article you may want to go to the Gallup Poll Web site, https: It is important to be mindful of margin or error as discussed in this article.

We all need to remember that public opinion on a given topic cannot be appropriately measured with one question that is only asked on one poll. Such results only provide a snapshot at that moment under certain conditions. The concept of repeating procedures over different conditions and times leads to more valuable and durable results.

Within this section of the Gallup article, there is also an error: In 5 of those surveys, the confidence interval would not contain the population percent. Eberly College of Science. Printer-friendly version Sampling Methods can be classified into one of two categories: Sample has a known probability of being selected Non-probability Sampling: Sample does not have known probability of being selected as in convenience or voluntary response surveys Probability Sampling In probability sampling it is possible to both determine which sampling units belong to which sample and the probability that each sample will be selected.

Simple Random Sampling SRS Stratified Sampling Cluster Sampling Systematic Sampling Multistage Sampling in which some of the methods above are combined in stages Of the five methods listed above, students have the most trouble distinguishing between stratified sampling and cluster sampling. With stratified sampling one should: With cluster sampling one should divide the population into groups clusters.

Stratified sampling would be preferred over cluster sampling, particularly if the questions of interest are affected by time zone.


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The following Slideshare presentation, Sampling in Quantitative and Qualitative Research – A practical how to, offers an overview of sampling methods for quantitative research and contrasts them with qualitative method for further understanding.

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RESEARCH METHOD - SAMPLING 1. Sampling Techniques & Samples Types 2. Outlines Sample definition Purpose of sampling Stages in the selection of a sample Types of sampling in quantitative researches Types of sampling in qualitative researches Ethical Considerations in Data Collection.

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Sampling is the process of selecting units (e.g., people, organizations) from a population of interest so that by studying the sample we may fairly generalize our results back to the population from which they were chosen. Once you know your population, sampling frame, sampling method, and sample size, you can use all that information to choose your sample. Importance As you can see, choosing a sample is a.

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There are many methods of sampling when doing research. This guide can help you choose which method to use. Simple random sampling is the ideal, but researchers seldom have the luxury of time or money to access the whole population, so many compromises often have to be made. Multistage Sampling (in which some of the methods above are combined in stages) Of the five methods listed above, students have the most trouble distinguishing between stratified sampling and cluster sampling.