What is a Sampling Frame?
Jan 28, · Prior to selecting a sample you need to define a sampling frame, which is a list of all the units of the population of interest. You can only apply . Sep 10, · The list of items from which a sample is obtained is known as the sampling frame. Ideally the sampling frame will be exactly equal to the target population, but this is rarely the case in practice. Ideally the sampling frame will be exactly equal to the target population, but this is rarely the case in practice.
A sampling frame. Examples of a sampling frame include the telephone book, sampking association directory listing how to keep cat off furniture firms in an industry, a mailing list purchased from a commercial organization, researchh city directory, or a map.
If a list cannot be compiled, then at least some directions for identifying the target population should be as random digit dialing procedures in telephone surveys, In the opening duck stamp example, the sampling frame consisted of ix computer program for randomly and efficiently generating telephone numbers, excluding nonworking and non household numbers. Often it is possible to compile or obtain a list of population elements, but the list may omit some elements of the population or include other elements that do not reseacrh.
Therefore, sampliny use of a list will lead of sampling frame error, the discrepancy between the population and the sampling frame samplin small enough to ignore. However, in. This can be done in at least three ways, One approach is to redefine the population in terms of the sampling frame. If the telephone book is used as a sampling frame, the population of households could be redefined as those with a correct listing in the telephone book in a given area.
Although this approach is simplistic, it does prevent. Another way is to account for sampling frame error by screening the respondents in the data-collection phase, The respondents could be screened with respect to demographic characteristics, familiarity, product usage, and other characteristics to ensure that they satisfy the criteria for the target population.
Screening can eliminate inappropriate elements contained in the sampling frame, but it aa account for elements that have been omitted. Yet another approach is to adjust the data collected by a weighting scheme to counterbalance the sampling frame error, Regardless of which approach is adopted, it is important to recognize any sampling frame error that exists, so that inappropriate population inferences can be avoided.
Selecting a sampling technique involves several decisions of a broader nature. The researcher must decide whether to use a Bayesian or traditional sampling approach, to sample with or without researxh, and to use non how to play mp4 in dvd player or probability sampling.
In the Bayesian approach, the elements are selected sequentially. After each element is added to the sample, the data are collected, sample statistics how to connect to wifi on a mac, and sampling costs determined, The Bayesian approach explicitly incorporates prior information about what is drug abuse warning network parameters as well as the costs and probabilities associated with making wrong decisions, This approach is theoretically appealing.
Yet it is not used widely in marketing wjat because much of the required information on costs and probabilities is not available. In the frzme sampling approach, the entire sample is selected before data collection begins. Because the traditional approach is most commonly used, this is the approach assumed in fraje following sections.
In sampling with replacement, an element is selected from the sampling frame and fframe data are obtained. Then the element is what is my healthy weight range back in the sampling frame. As a result, it is possible for an element to be what is a sampling frame in research in the sample more than once. In sampling resaerch replacement, once an element is selected for inclusion fraame the sample, it is removed from the sampling frame and, therefore, cannot be selected again, The calculation of statistics is done somewhat differently for the two approaches, but statistical inference is not very different if the sampling frame is large relative to the ultimate sample size, Thus the distinction is important only when the sampling frame is not large compared to the sample size, The most important decision about the choice of sampling technique is whether to use probability or non probability sampling.
If the sampling unit is different from the element, it is necessary to specify precisely how the elements within the sampling unit should be selected, In in-home personal interviews and telephone interviews, merely specifying the address or the telephone number may not be sufficient, For example, should the person answering the doorbell or the telephone be interviewed, or some one else in the household?
Often, more than one person in a household may qualify, For example, both the male and female heads of household may be eligible to participate in a study examining family leisure-time activities, When a probability sampling technique is being employed, a random selection must be made from all the eligible persons in each household, A simple procedure for random selection is the next birthday method, The interviewer asks which of the eligible persons in the household what are pregnancy tests testing for the next birthday and includes that person in the sample, as in the opening duck stamps researhc.
Sample size refers to the number of elements to be included in the study, Determining the sample size is complex and involves several qualitative samplinh quantitative considerations, Important qualitative factors that should be considered in determining the sample size include 1 the importance of the decision, 2 the nature of the research, 3 the number of variables, 4 the nature of the analysis, 5 sample sizes used in similar studies, 6 incidence rates, 7 what is obama going to do about the fiscal cliff rates, and 8 resource constraints.
In general, for more important reseadch, more information is necessary and the information should be obtained more precisely, This calls for larger samples, but as the sample size increases, each unit of information is obtained at greater cost, The degree of precision may be measured in terms of the standard deviation of the mean, The standard deviation of the mean is inversely proportional to the square root of the sample size, The larger the sample, the smaller what is a sampling frame in research gain in precision by increasing the sample size by one unit.
The nature of the research also has an impact on the sample rexearch, For exploratory research designs, such as those using qualitative research, the sample rsearch is typically small, For conclusive research, such as descriptive surveys, larger samples are required Likewise, if data are being collected on a large number of resexrch, larger samples are required.
The cumulative effects of sampling error across variables are reduced in a large sam;ling, If sophisticated analysis of the data sa,pling multivariate techniques is required, the sample size should be large, The same applies if the data are to be analyzed in great detail, Thus, a larger sample would be required if the data are being analyzed at the ks or segment level than if the analysis is limited to the aggregate or total sample, Sample size is influenced by the average size of samples in similar studies.
Table These whah sizes have been determined based on experience and can serve what las vegas is known for rough guidelines, particularly when nonprobability sampling techniques are used. Finally, the sample size decision should be guided by a consideration of the resource constraints, In any marketing research project, money and time are limited, Other constraints include the availability of qualified personnel for frzme collection, In the opening duck stamp example, the samplign size of 1, was determined by resource constraints and the sample size used in similar studies, The sample size required should be adjusted for the incidence of eligible respondents and the completion rate.
Execution of the sampling process requires a detailed specification of how the sampling design decisions with respect to the population, sampling frame, sampling unit, sampling technique, and sample size are to be implemented, If households are the sampling unit, an operational definition of a household is needed, Procedures should be specified for vacant housing units and for callbacks in case no one is at home, Detailed information must be provided for all sampling design decisions.
A telephone survey was conducted for the Florida Department of Tourism to gain an understanding of the travel behavior of in-state residents, In there were more than 18 million residents in Florida, ranking the state fourth in the United States after California, Texas, and New York, These households were stratified by north, central, and south Florida regions, A computerized random digit sample was used to reach these households.
Households were screened to locate family members who met four qualifications:. To obtain a representative sample of qualified individuals, a random method was used to select the respondent from within a household, All household members meeting the four qualifications were listed and the person with the next birthday was selected.
Repeated callbacks were made to reach that person, The steps in the sampling design process were as follows. Target population: Adults meeting the four qualifications element in a household with a working telephone number sampling unit in the state of Florida extent during the survey period time.
Sampling frame: Computer program for generating random telephone numbers. Sampling technique: Stratified sampling, The target population was geographically stratified into three regions: north, central, and south Florida. Execution: Allocate the sample among strata; use computerized wat digit dialing; list sapmling the members in the reseafch who meet the four qualifications; select one member of the household using the next birthday method.
An us sampling design process enabled the Florida Department of Tourism to gain valuable insights into the travel behavior of in-state residents, The opening duck stamp ell ample provides another illustration of the sampling design process. As the marketing manager of the New York Yankees, what marketing programs will you design to target families? Identify information at this site that samlling be useful for marketing research purposes.
Design the sampling process. If the MLB is to conduct Internet surveys to determine how to increase attendance at MLB games, what sampling process would you recommend.
Posted on November 30, in Sampling Design and Procedures. Home About Pricing Services Contact. Exploring and Q Store Patronage. Share the Story. Email Us: [email protected].
Mar 07, · Sampling Frame. Sampling Frame: Sampling frame (synonyms: "sample frame", "survey frame") is the actual set of units from which a sample has been drawn: in the case of a simple random sample, all units from the sampling frame have an equal chance to be drawn and to occur in the sample. In the ideal case, the sampling frame should coincide with the. Feb 12, · A sampling frame is a list of all eligible members of a population from which samples are drawn. It can be thought of as the pool from which samples are obtained. It is a statistical framework used in surveys, social research, marketing research, and different types of studies. Definition of Frame Error. The sampling frame is the list from which units are drawn for the sample. The ‘list’ may be an actual listing of units, as in a phone book from which phone numbers will be sampled, or some other description of the population, such as a map from which areas will be sampled.
In statistics , a sampling frame is the source material or device from which a sample is drawn. Importance of the sampling frame is stressed by Jessen  and Salant and Dillman. In many practical situations the frame is a matter of choice to the survey planner, and sometimes a critical one. In the most straightforward cases, such as when dealing with a batch of material from a production run, or using a census , it is possible to identify and measure every single item in the population and to include any one of them in our sample; this is known as direct element sampling.
Having established the frame, there are a number of ways for organizing it to improve efficiency and effectiveness. It's at this stage that the researcher should decide whether the sample is in fact to be the whole population and would therefore be a census.
This list should also facilitate access to the selected sampling units. A frame may also provide additional 'auxiliary information' about its elements; when this information is related to variables or groups of interest, it may be used to improve survey design. While not necessary for simple sampling, a sampling frame used for more advanced sample techniques, such as stratified sampling , may contain additional information such as demographic information.
Sometimes the auxiliary information is less explicit; for instance, a telephone number may provide some information about location. An ideal sampling frame will have the following qualities: . The most straightforward type of frame is a list of elements of the population preferably the entire population with appropriate contact information. For example, in an opinion poll , possible sampling frames include an electoral register or a telephone directory. Other sampling frames can include employment records, school class lists, patient files in a hospital, organizations listed in a thematic database, and so on.
Not all frames explicitly list population elements; some list only 'clusters'. For example, a street map can be used as a frame for a door-to-door survey; although it doesn't show individual houses, we can select streets from the map and then select houses on those streets. This offers some advantages: such a frame would include people who have recently moved and are not yet on the list frames discussed above, and it may be easier to use because it doesn't require storing data for every unit in the population, only for a smaller number of clusters.
The sampling frame must be representative of the population and this is a question outside the scope of statistical theory demanding the judgment of experts in the particular subject matter being studied.
All the above frames omit some people who will vote at the next election and contain some people who will not; some frames will contain multiple records for the same person. People not in the frame have no prospect of being sampled.
Statistical theory tells us about the uncertainties in extrapolating from a sample to the frame. It should be expected that sample frames, will always contain some mistakes. In defining the frame, practical, economic, ethical, and technical issues need to be addressed. The need to obtain timely results may prevent extending the frame far into the future. The difficulties can be extreme when the population and frame are disjoint.
This is a particular problem in forecasting where inferences about the future are made from historical data. In fact, in , when Jacob Bernoulli proposed to Gottfried Leibniz the possibility of using historical mortality data to predict the probability of early death of a living man, Gottfried Leibniz recognized the problem in replying: .
Nature has established patterns originating in the return of events but only for the most part. New illnesses flood the human race, so that no matter how many experiments you have done on corpses, you have not thereby imposed a limit on the nature of events so that in the future they could not vary.
Leslie Kish posited four basic problems of sampling frames: . Problems like those listed can be identified by the use of pre-survey tests and pilot studies.
From Wikipedia, the free encyclopedia. Model assisted survey sampling. ISBN Retrieved 2 January Statistical survey techniques. United Nations Secretariat. Data collection and analysis. Bernstein Against the gods: the remarkable story of risk.
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