How to select a sampling Technique and survey method

A sample is a part of an entire population that possesses attitudes, opinions, habits, or
characteristics that you wish to study. A census includes an entire population. Consider the size
of the population you’re sampling, and then decide whether you want to survey a sample
or a census. If you elect to survey a sample, you might use one of the following techniques.

Purposive sampling
Use non-probabilistic or purposive sampling, if you want to learn about people with special
characteristics. Purposive sampling is often used for focus groups.

Example:
You want to survey females between the ages of 18 and 25 who watch television
at least 10 hours a week. (yep, days of our lives)You’ll want to conduct a purposive sample, to be
sure that you include all of the relevant characteristics and exclude individuals
who don’t fit these requirements. Using every “nth” name Systematic sampling, the easiest random sampling method, generates a multiple of a number: for example, every 5th, 10th, or 34th name from a population list. Beware of hidden patterns in your list that could compromise the integrity of the sample, however. The list may include names sorted by frequency or recency
of contact, geographic origin, or similar company size.
Using more than one sampling method You may use more than one sampling method for your survey. You may conduct a simple random sample but purposely over-sample one
stratum—households with a certain level of income, for example. With these additional data, you can perform two studies: one on the whole population and the other on a specific subset. This
type of sample is called a stratified sample.

Choose a survey method
There are two basic methods for conducting a survey: self-administered and interviewer administered.
Self-administered surveys can be written—a paper questionnaire handed out to respondents or sent by mail, or conducted electronically via the Web. Self-administered surveys
can also be oral. Interviewer administered
surveys can be conducted in person or over the phone, with interviewers recording results on paper or electronically. If questions are personal or require a lot of thought, self-administered
surveys are a good choice.