scholarly journals Minimizing the Cost in Sample Size Computation

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Jiangao Luo
Keyword(s):  
Sample Size ◽  
The Cost

Optimal design with variable cost and precision requirements

1989 ◽  
Vol 19 (12) ◽  
pp. 1591-1597
Author(s):  
Margaret Penner
Keyword(s):  
Biological Sciences ◽  
Optimal Design ◽  
Sample Size ◽  
Design Theory ◽  
Sampling Design ◽  
Unit Cost ◽  
Evaluation Process ◽  
Variable Cost ◽  
Design Flexibility ◽  
The Cost

A method for incorporating variable costs and differing precision requirements into optimal design theory is developed and discussed. In many studies and experiments, particularly in the biological sciences, the cost of each observation can vary considerably depending on the attributes of the sample. Ignoring observation costs leads to designs that maximize precision for a given sample size. However, by incorporating costs, efficiency is maximized by optimizing precision per unit cost. An example is presented that demonstrates the efficiency of a weighted optimal design in comparison with several alternatives. The weighted optimal design is most efficient at meeting the experimenter's precision objectives. Comparing designs allows the introduction of additional criteria such as design flexibility into the evaluation process. Explicitly incorporating both cost and precision in the search for a sampling design ensures time is wisely spent considering study objectives, including precision requirements.

scholarly journals The Determination of Sample Size for Sensitive Issue Successive Survey with the Multiplication RRT Model under Two-Stage and Stratified Two-Stage Random Sampling and Its Application in Medical Survey

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Bo Yu ◽  
Xiaonan Liang ◽  
Ying Wang ◽  
Yun Liu ◽  
Qiao Chang ◽  
...  
Keyword(s):  
Sample Size ◽  
Sampling Method ◽  
Sampling Errors ◽  
Two Stage ◽  
Successive Sampling ◽  
Optimal Sample ◽  
Sensitive Issue ◽  
Survey Accuracy ◽  
The Cost

When designing the sample scheme, it is important to determine the sample size. The survey accuracy and cost of survey and sampling method should be considered comprehensively. In this article, we discuss the method of determining the sample size of complex successive sampling with rotation sample for sensitive issue and deduce the formulas for the optimal sample size under two-stage sampling and stratified two-stage sampling by using Cauchy-Schwartz inequality, respectively, so as to minimize the cost for given sampling errors and to minimize the sampling errors for given cost.

Sample Size, Power Calculations, and Their Implications for the Cost of Thorough Studies of Drug Induced QT Interval Prolongation

2004 ◽  
Vol 27 (12) ◽  
pp. 1659-1669 ◽  
Author(s):  
MAREK MALIK ◽  
KATERINA HNATKOVA ◽  
VELISLAV BATCHVAROV ◽  
YI GANG ◽  
PETER SMETANA ◽  
...  
Keyword(s):  
Sample Size ◽  
Qt Interval ◽  
Interval Prolongation ◽  
Drug Induced ◽  
Power Calculations ◽  
Qt Interval Prolongation ◽  
The Cost

Optimal Sampling for Identifying a Cluster: An Application in Sorting

1993 ◽  
Vol 7 (3) ◽  
pp. 387-407
Author(s):  
Shmuel Gal ◽  
Dafna Sheinwald
Keyword(s):  
Sample Size ◽  
Sequential Sampling ◽  
A Priori ◽  
Optimal Sampling ◽  
Truncation Point ◽  
Fixed Sample Size ◽  
Fixed Sample ◽  
A Priori Distribution ◽  
Sampling Procedures ◽  
The Cost

We consider the following problem. For a given population of m items, we have to make a decision whether or not the population includes a relatively large cluster of identical items. This decision affects the effectiveness of a subsequent computational process, depending on the actual existence of the cluster and its size. To make a good decision, we use a statistical sample which should indicate the existence of a cluster and find a representative thereof. This paper describes the optimal sampling technique to be used in such a case, given the cost of the sampling and the potential gain in speed of the subsequent process. The optimal fixed sample size is specified, as well as the optimal sequential sampling, along with characterizing the dependence of the cost function on the truncation point.For the case that the a priori distribution of the cluster proportion is known, we present formulae by which the optimal sampling procedures can be easily calculated. For the common situation in which the a priori distribution is not known, we present, in the case of a fixed sample size, a tight upper bound for the sample size, which is independent of the a priori distribution, and for the case of the sequential sampling, we present an approximately optimal truncation point, which is also independent of the a priori distribution.The situation described arose in connection with choosing the best sorting method, an application that will be described in full detail. The most interesting practical result is that for our application truncating the sequential procedure at 35 observations, out of a population of 25,000–30,000 items, guarantees that in our sorting application we are always within 2.1% of the optimal cost independently of the a priori distribution.

Systematic review of the cost-effectiveness of sample size maintenance programs in studies involving postal questionnaires reveals insufficient economic information

2012 ◽  
Vol 65 (10) ◽  
pp. 1031-1040 ◽  
Author(s):  
Michael C. David ◽  
Mark Bensink ◽  
Hideki Higashi ◽  
Roslyn Boyd ◽  
Lesley Williams ◽  
...  
Keyword(s):  
Systematic Review ◽  
Cost Effectiveness ◽  
Sample Size ◽  
Economic Information ◽  
The Cost

scholarly journals Quasi-reliable estimates of effective sample size

2020 ◽  
Author(s):  
Youhan Fang ◽  
Yudong Cao ◽  
Robert D Skeel
Keyword(s):  
Sample Size ◽  
Dimensional Subspace ◽  
Monte Carlo Algorithm ◽  
Finite Dimensional Subspace ◽  
Effective Sample Size ◽  
Finite Dimensional ◽  
Adequate Sampling ◽  
Autocorrelation Time ◽  
The Mean ◽  
The Cost

Abstract The efficiency of a Markov chain Monte Carlo algorithm for estimating the mean of a function of interest might be measured by the cost of generating one independent sample, or equivalently, the total cost divided by the effective sample size, defined in terms of the integrated autocorrelation time. To ensure the reliability of such an estimate, it is suggested that there be an adequate sampling of state space— to the extent that this can be determined from the available samples. A sufficient condition for adequate sampling is derived in terms of the supremum of all possible integrated autocorrelation times, which leads to a more stringent condition for adequate sampling than that simply obtained from integrated autocorrelation times for functions of interest. A method for estimating the supremum of all integrated autocorrelation times, based on approximation in a finite-dimensional subspace, is derived and evaluated empirically.

scholarly journals Challenges Associated with Postgraduate Students’ Awareness and Use of Online Journals in Nigerian Universities

2020 ◽  
Vol 11 (1) ◽  
pp. 16-24
Author(s):  
Austin J.C . Mole ◽  
Nelson Edewor
Keyword(s):  
Sample Size ◽  
Service Providers ◽  
Survey Design ◽  
Sample Size Determination ◽  
University Libraries ◽  
Internet Service ◽  
Postgraduate Students ◽  
Online Journals ◽  
The Cost ◽  
Descriptive Survey

This study investigates the challenges associated with postgraduate students’ awareness and use of online journals in Nigerian universities. The study adopted the descriptive survey design. The population of the study comprised 10, 775 registered postgraduate students in federal and state universities in south-south zone of Nigeria. Based on the Krejcie and Morgan sample size determination table, a sample size of 370 postgraduate students were chosen for the study. The questionnaire was the instrument used for data collection. Copies of the questionnaire were distributed by hand by the researchers with the help of research assistants. Mean and standard deviation were used to analyse the data from the questionnaire. The major findings challenges associated with postgraduate students’ awareness and use of online journals were identified to include absence of enlightenment on online journals by lecturers (𝑋̅2.94,SD=.87), lack of knowledge of publishers of online journals (𝑋̅2.67,SD=.98), lack of user education on online journals from university libraries (𝑋̅2.80,SD=.93), inadequate computer systems in university libraries (𝑋̅3.58,SD=.73), frequent power outages in libraries (𝑋̅3.48,SD=.66), and slow internet connectivity in university libraries (𝑋̅2.96,SD=.94) among others. Respondents in the study proffered several strategies for enhancing awareness and use of online journals. Based on the findings, it was recommended that the cost of data bundle should be reduced by Internet service providers, particularly for postgraduate students to enhance the use of online journals. University libraries should engage in aggressive awareness campaign on online journals and their usefulness for effective research in universities. Additionally, university libraries should create a database of open access online journals to enable users search full text articles online from various publishers. Keywords:  Online Journals, Awareness, Use, Universities, Challenges

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