One of the most common and recognized techniques that researchers use to gather information when conducting a poll is referred to as the probability sampling method. According to Austin and Pinkleton, “Researches generate probability samples using a random selection process so that each member of a population has an equal chance, or probability, of being included in a sample.” Yet, in order for there to be a random selection method, researchers must set up some process or procedure to assure that every person in a selected population has an equal chance of being chosen. The most common and basic type of probability sampling is known as simple random selection since it allows researchers to make accurate predictions about a certain population based on the information they collect from a sample.

In the book entitled, Strategic Public Relations Management: Planning and Managing Effective Communication Programs by Austin and Pinkleton, the authors suggest that in order to produce a simple random sample, researches must ensure that each member of a population has the same probability of being selected in a sample and choose each sample element separately. The book states, “Simple random sampling is the most basic method of random sampling, and investigators use it to ensure that the sample they produce is representative of the population.” Yet, in order to be certain that each member of a population is selected at random, researchers must identify each member of a population through the use of a comprehensive sampling frame. Oftentimes, researchers will take a list of population members for a sample frame and number each one sequentially. Afterwards, each member is selected to be in a sample group from either a table of random numbers or from a program on the computer that selects numbers at random. According to Austin and Pinkleton, both types of methods typically produce a random sample that is highly representative of its population.

The book includes an example of a simple random sample that could be used if the Public Relations Society of America (PRSA) wanted to survey its members to determine their level of satisfaction with its programs and services. In order to be certain that each member was selected at random, a project manager could take the PRSA’s membership list and assign numbers to each member sequentially. Afterwards, the manager could choose numbers at random and match them to the ones that each PRSA member was assigned. If conducted properly, the process would produce a sample of individuals who have a high likelihood of accurately representing the attitudes and opinions of every member in PRSA.

In the book entitled, A Journalist’s Guide to Public Opinion Polls by Gawiser and Witt, the authors suggest that a simple random sample is when every individual in a population has the same probability of being selected in a sample and the selection of one individual over another does not impact the selection of another. In addition, the authors suggest that unlike many other sampling methods, this one has a number of selection techniques that have proven to be successful at making sure that every member of a population is selected at random.

The book includes an example of how a researcher could go about conducting a simple random sample of 1,000 undergraduate students at a small university. It says that in order to be certain that every undergraduate student has the same probability of being selected, the researcher could write the names of the 1,000 undergraduate students on separate pieces of paper and put them into a hat. After mixing all of the slips of paper together, the researcher could draw 100 slips out of the hat and those names written on the pieces of paper would be the individuals in the sample group. If conducted properly, the process would produce a sample of students who have a high likelihood of representing the attitudes and opinions of all the undergraduate students at the university.

On October 22, 1980, Harvard University conducted a poll using the probability sampling method. Out of nearly 20,000 undergraduate students, researchers randomly selected 2,500 of them from a computer database to survey. Each student was asked whether or not they believed faculty members at Harvard cared about their academic problems. The results indicated that nearly half of Harvard undergraduate students believe that most faculty members at the university do not care about their academic problems. Although the findings of this poll are rather interesting, it is important to note that Harvard University met the criteria of selecting their sample population by using the sample random selection technique. This is because every undergraduate student had the same chances of being chosen since a computer database randomly chose 2,500 of them to survey.

Each of the examples in both of the books and the survey that was conducted at Harvard University represent the criteria that must be met in order for probability sampling to be considered a simple random selection. Not only must every member of a population have an equal chance of being included in a sample, but also the selection of one individual over another cannot impact the selection of another. Moreover, it is important to keep in mind that when a simple random selection is conducted properly, the results are highly representative of the attitudes and opinions of its entire population.

## Reaction Paper on Sampling Methods II: Probability Sampling

March 7, 2010 by iowajournalism

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