• School Mathematics
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• v.16 no.4
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• pp.727-743
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• 2014

The concepts of sample and sampling are central to the statistical thinking and foundations of the statistical literacy, so we need to be emphasized their importance in the statistics education. However, many researches which dealt with samples only analyze textbooks or students' responses. In this study, the concept of sample is addressed by a historical consideration which is one aspect of the didactical analysis. Moreover, developing concept of sample is analyzed from the preceding studies about the statistical literacy, considering the sample representativeness and the sampling variability. The results say that the historical process of developing the concept of sample can be divided into three step: understanding the sample representativeness; appearing the sample variance; recognizing the sampling variability. Above all, it is important to aware and control the sampling variability, but many related researches might not consider sample variability. Therefore, it implies that the awareness and control of sampling variability are needed to reflect to the teaching-learing of sample for developing the students' statistical literacy.

• Communications for Statistical Applications and Methods
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• v.10 no.3
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• pp.647-654
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• 2003

Bayesian probability models for finite populations are considered assuming so-called the super-population. We find the posterior distribution of population mean by a new approach, using the concept of pivotal quantity for the small sample case. A large sample theory is also treated throught the concept of asymptotically pivotal quantity.

• Journal of Educational Research in Mathematics
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• v.15 no.4
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• pp.445-459
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• 2005

Statistics education is considered within the mathematics curriculum and, thus, can be integrated into other areas of mathematics. However, statistical concepts and thinking skills have to be considered as very different from those of other areas. It is possible to make statistics more meaningful for the learner by making definitions or explanations of concepts in textbooks more clear and consistent. In 'Math I' and 'Probability & Statistics' of the 7th curriculum, the definitions of sample standard deviation are different, which might confuse students. In this study, firstly, some issues relevant to sample standard deviation concept are discussed through the analysis in terms of didactical situation and curriculum. Secondly, the characteristics of sample standard deviation concept as a scholarly knowledge are examined. Finally, the characteristics of didactic transposition of sample standard deviation concept in Japanese, American, and British textbooks are investigated and some suggestions are elicited.

• The Mathematical Education
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• v.59 no.1
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• pp.47-62
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• 2020

Understanding the concept of probability distribution becomes more important. We considered probabilities defined in the sample space, the definition of discrete random variables, the probability of defined discrete probability distribution, and the relationship between them as knowledge of discrete probability distribution, and investigated the understanding degree of the mathematics preservice teachers. The results are as follows. Firstly, about 70% of preservice teachers who participated in this study expressed discrete probability distribution graphs in ordered pairs or continuous distribution. Secondly, with regard to the two factors for obtaining discrete probability distributions: probability for each element in the sample space and the concept of random variables that convert each element in the sample space into a real value, only 13% of the preservice teachers understood and addressed both factors. Thirdly, 39% of the preservice teachers correctly responded to whether different probability distributions can be defined for one sample space. Fourthly, when the probability of each fundamental event was determined to obtain the probability distribution of the discrete random variables defined in the undefined sample space, approximately 70% habitually calculated by the uniform probability. Finally, about 20% of preservice teachers understood the meaning and relationship of binomial distribution, discrete random variables, and sample space. In relation, clear definitions and full explanations of concept need to be provided from textbooks and a program to improve the understanding of preservice teachers need to be developed.

• Journal of the Korean Home Economics Association
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• v.40 no.4
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• pp.179-200
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• 2002

The purposes of this study are as follows: (1) how are marital relationships classified by wives' perception of marital conflict and intimacy? (2) how do these types differ in terms of demographic variables (age, income, educational level, and employment status), individual psychological variables (self-esteem, differentiation) and interaction-related variables (affective self-disclosure, conflict resolution styles)?, and what are the relative discriminant powers of these variables in explaining marriage types? The data for this study were collected from 944 married women in Dajeon, who had one or more children, using the structured questionnaire. Classification using median and discriminant analysis were used with SPSS-PC for windows program. The major findings are as follows: The characteristics of each type are as follows: (1) The 'devitalized couples' consist of 18.2% of the whole sample. The levels of positive self-concept and positive interaction are the lowest. (2) The 'intimate couples' consist of 32.6% of the sample. They tend to be found most frequently in the population which is high in the educational level and income level and low in age. While the levels of positive self-concept and positive interaction are the highest, the levels of negative conflict resolution styles are the lowest. (3) The 'intimacy-persuaded couples' take 17.3% of the sample. The levels of positive self-concept and interaction are similar to the 'intimate couples'. (4) The 'conflict-habituated couples' take 31.9% of the sample. Whereas the levels of negative conflict resolution styles are the highest, the levels of positive self-concept and positive interaction are the lowest. The results of this study suggest several implications for the family-life education. It needs to apply different approaches to improve marital quality for each type of marriage.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.18-27
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• 1993

In this paper, the concept of sampling vectors is introduced, and used for a simple realization of DSSs(distributed sample scramblers). In DSSs, if the sampling times of the scrambler state samples are not identical to their transmission times, samples are delayedtransmitted to the descrambler. and in this case the DSSs need additional memory elements storing the samples and additional clocks for informing their transmission times. The concept of sampling vectors helps move the sampling times of delayed samples to their transmission times, thus eliminating the additional memory elements and clocks in the DSSs. In the paper, the conditions on the synchronization of the scrambler and descrambler are derived for the DSS employing sampling vectors,and demonstrations are given on their applicaitons to cell-based ATM DSSs.

• Journal of The Korea Institute of Healthcare Architecture
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• v.1 no.1
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• pp.69-78
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• 1995

This study is intended to understand the architectural characteristics and trends of general hospitals in Europe. The Observations, interviewes with the staff, and analyses of related materials were executed through the study-visits of sample hospitals. Some results of the study could be summarized as follows : (1) The architectural characteristics of sample hospitals could be described as the realization of horizontal design concept, application of urban design method, specialization of service departments, intergration of facility design, and planning for the emergency & disaster. (2) The architectural trends of sample hospitals could be suggested as the decentralization of functions, promotion of building standard, enhancement of interior space, consideration of environment, and autonomous management & operation of facilities. (3) The humanistic and environmental approaches from european hospitals would be preferably applicable rather than the popular concept of automation, ultra-modernization and mega-structure in Korea. First of all, the bed-center and proper facilities for disaster should be considered.

• International Journal of Reliability and Applications
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• v.1 no.2
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• pp.123-131
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• 2000

This paper concerns with the consistent estimator for the fuzzy expectation of a random variable taking values in the space F($R^p$) of upper semicontinuous convex fuzzy subsets of $R^p$ with compact support. We introduce the concept of a fuzzy sample mean and show that the fuzzy sample mean is a strong consistent estimator for the fuzzy expectation. Some examples are given to illustrate the main result.

• Journal of Veterinary Clinics
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• v.31 no.4
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• pp.288-292
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• 2014

A critical assumption of the standard sample size calculation is that the response (outcome) for an individual patient is completely independent to that for any other patient. However, this assumption no longer holds when there is a lack of statistical independence across subjects seen in cluster randomized designs. In this setting, patients within a cluster are more likely to respond in a similar manner; patient outcomes may correlate strongly within clusters. Thus, direct use of standard sample size formulae for cluster design, ignoring the clustering effect, may result in sample size that are too small, resulting in a study that is under-powered for detecting the desired level of difference between groups. This paper revisit worked examples for sample size calculation provided in a previous paper using nomogram to easy to access. Then we present the concept of cluster design illustrated with worked examples, and introduce design effect that is a factor to inflate the standard sample size estimates.

• The Mathematical Education
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• v.55 no.3
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• pp.317-334
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• 2016

Knowledge and data interpretation on statistical estimation was important to have statistical literacy that current curriculum was said not to satisfy. The author investigated mathematics teachers' MKT on statistical estimation concerning interpretation of confidence interval by using questionnaire and interview. SMK of teachers' confidence was limited to the area of textbooks to be difficult to interpret data of real life context. Most of teachers wrongly understood SMK of interpretation of confidence interval to have influence upon PCK making correction of students' wrong concept. SMK of samples and sampling distribution that were basic concept of reliability and confidence interval cognized representation of samples rather exactly not to understand importance and value of not only variability but also size of the sample exactly, and not to cognize appropriateness and needs of each stage from sampling to confidence interval estimation to have great difficulty at proper teaching of statistical estimation. PCK that had teaching method had problem of a lot of misconception. MKT of sample and sampling distribution that interpreted confidence interval had almost no relation with teachers' experience to require opportunity for development of teacher professionalism. Therefore, teachers were asked to estimate statistic and to get confidence interval and to understand concept of the sample and think much of not only relationship of each concept but also validity of estimated values, and to have knowledge enough to interpret data of real life contexts, and to think and discuss students' concepts. So, textbooks should introduce actual concepts at real life context to make use of exact orthography and to let teachers be reeducated for development of professionalism.