• Title/Summary/Keyword: two-proportions

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Symmetry, ratio and proportion in Scottish clan tartans - Templates for modern designers -

  • Hann, Michael;Wang, Chaoran
    • The Research Journal of the Costume Culture
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    • v.24 no.6
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    • pp.873-885
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    • 2016
  • It is common knowledge that a conventionally woven textile consists of two assemblies of parallel threads (warp and weft), one interlaced with the other at ninety degrees. Where each of the two assemblies is arranged in a particular colour sequence, a check design, known as a 'tartan', may be created. Although similar check-type cloths have been produced worldwide, it is the tartans of Scotland which have received most attention and it is here that a complex set of rules evolved and tartans of different types became associated traditionally with different regions, family groups or 'clans'. There is an impressive array of publications focused on the identification of tartans and their clan associations. This paper explains the nature of tartans, analyses typical surface structures, ratios and proportions, and suggests possible avenues of use for modern designers. The principal sources of data were a collection of tartans held at ULITA - An Archive of International Textiles (University of Leeds, UK) and Stewart's 1974 publication The Setts of Scottish Tartans. Based on the observation that divisions into halfs and thirds were dominant, a series of templates is presented with the intention of developing an awareness among designers that ratios and proportions used in familiar or traditional frameworks can be employed in a modern context.

Hypothesis Testing: Means and Proportions (평균과 비율 비교)

  • Pak, Son-Il;Lee, Young-Won
    • Journal of Veterinary Clinics
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    • v.26 no.5
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    • pp.401-407
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    • 2009
  • In the previous article in this series we introduced the basic concepts for statistical analysis. The present review introduces hypothesis testing for continuous and categorical data for readers of the veterinary science literature. For the analysis of continuous data, we explained t-test to compare a single mean with a hypothesized value and the difference between two means from two independent samples or between two means arising from paired samples. When the data are categorical variables, the $x^2$ test for association and homogeneity, Fisher's exact test and Yates' continuity correction for small samples, and test for trend, in which at least one of the variables is ordinal is described, together with the worked examples. McNemar test for correlated proportions is also discussed. The topics covered may provide a basic understanding of different approaches for analyzing clinical data.

Comparison Density Representation of Traditional Test Statistics for the Equality of Two Population Proportions

  • Jangsun Baek
    • Communications for Statistical Applications and Methods
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    • v.2 no.1
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    • pp.112-121
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    • 1995
  • Let $p_1$ and $p_2$ be the proportions of two populations. To test the hypothesis $H_0 : p_1 = p_2$, we usually use the $x^2$ statistic, the large sample binomial statistic Z, and the Generalized Likelihood Ratio statistic-2log $\lambda$developed based on different mathematical rationale, respectively. Since testing the above hypothesis is equivalent to testing whether two populations follow the common Bernoulli distribution, one may also test the hypothesis by comparing 1 with the ratio of each density estimate and the hypothesized common density estimate, called comparison density, which was devised by Parzen(1988). We show that the above traditional test statistics ate actually estimating the measure of distance between the true densities and the common density under $H_0$ by representing them with the comparison density.

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Proportions of the aesthetic African-Caribbean face: idealized ratios, comparison with the golden proportion and perceptions of attractiveness

  • Mantelakis, Angelos;Iosifidis, Michalis;Al-Bitar, Zaid B.;Antoniadis, Vyron;Wertheim, David;Garagiola, Umberto;Naini, Farhad B.
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.40
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    • pp.20.1-20.10
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    • 2018
  • Background: In the absence of clear guidelines for facial aesthetic surgery, most surgeons rely on expert intuitive judgement when planning aesthetic and reconstructive surgery. One of the most famous theories regarding "ideal" facial proportions is that of the golden proportion. However, there are conflicting opinions as to whether it can be used to assess facial attractiveness. The aim of this investigation was to assess facial ratios of professional black models and to compare the ratios with the golden proportion. Methods: Forty photographs of male and female professional black models were collected. Observers were asked to assign a score from 1 to 10 (1 = not very attractive, 10 = very attractive). A total of 287 responses were analysed for grading behaviour according to various demographic factors by two groups of observers. The best graded photographs were compared with the least well-graded photographs to identify any differences in their facial ratios. The models' facial ratios were calculated and compared with the golden proportion. Results: Differences in grading behaviour were observed amongst the two assessment groups. Only one out of the 12 facial ratios was not significantly different from the golden proportion. Conclusions: Only one facial ratio was observed to be similar to the golden proportion in professional model facial photographs. No correlation was found between facial ratios in professional black models with the golden proportion. It is proposed that an individualistic treatment for each ratio is a rather better method to guide future practice.

Elementary Science Instruction Analysis According to Teacher의s Understanding Toward Science (과학에 대한 초등 교사의 인식에 따른 자연과 수업 분석)

  • 김상각;김효남
    • Journal of Korean Elementary Science Education
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    • v.17 no.2
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    • pp.91-101
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    • 1998
  • The purpose of this study was to find out how to be pursued elementary teachers' science instruction according to their understanding toward science. Sixty elementary teachers were involved in the questionnaire, investigating understanding on the nature of science and the science teaching. Two elementary teachers' science classes are observed. Their instructional objectives were analyzed. And their understanding toward science was measured. Teacher A had consistent modern philosophical views of science on the nature of science and science teaching, and teacher B had not consistency Klopfer's science educational objectives category was used to analyse instructional objective. The ideal proportions of the instructional objectives of the observed classes were established from science education specialist group. You ideality index was calculated. You ideality index indicate how far from the ideal proportions of the instructional objectives the observed instruction is. Relative proportions of instructional objectives appeared in science classes were compared with ideal instructional objectives. Instructional objectives containing the modem views appearing classes observed were compared according to teachers' understanding toward science. As results, teachers' understanding toward science showed lack of consistency, which is consisted of modern philosophical view of science on science teaching: modem and classical philosophical view of science on nature of science. Teacher A's instruction was approached more closely to the ideal proportions of the instructional objectives, showing fewer You ideality index. Instructional objectives containing the modern views are more appeared and closer to ideal proportions in teacher A's classes than in teacher B's. A teacher having modern understanding on nature of science would instruct science with modern scientific philosophical perspectives. Therefore teacher preparation programs should include more contents about modern philosophical understanding on the nature of science.

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Likelihood Based Confidence Intervals for the Difference of Proportions in Two Doubly Sampled Data with a Common False-Positive Error Rate

  • Lee, Seung-Chun
    • Communications for Statistical Applications and Methods
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    • v.17 no.5
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    • pp.679-688
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    • 2010
  • Lee (2010) developed a confidence interval for the difference of binomial proportions in two doubly sampled data subject to false-positive errors. The confidence interval seems to be adequate for a general double sampling model subject to false-positive misclassification. However, in many applications, the false-positive error rates could be the same. On this note, the construction of asymptotic confidence interval is considered when the false-positive error rates are common. The coverage behaviors of nine likelihood based confidence intervals are examined. It is shown that the confidence interval based Rao score with the expected information has good performance in terms of coverage probability and expected width.

Choosing between the Exact and the Approximate Confidence Intervals: For the Difference of Two Independent Binomial Proportions

  • Lee, Seung-Chun
    • Communications for Statistical Applications and Methods
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    • v.16 no.2
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    • pp.363-372
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    • 2009
  • The difference of two independent binomial proportions is frequently of interest in biomedical research. The interval estimation may be an important tool for the inferential problem. Many confidence intervals have been proposed. They can be classified into the class of exact confidence intervals or the class of approximate confidence intervals. Ore may prefer exact confidence interval s in that they guarantee the minimum coverage probability greater than the nominal confidence level. However, someone, for example Agresti and Coull (1998) claims that "approximation is better than exact." It seems that when sample size is large, the approximate interval is more preferable to the exact interval. However, the choice is not clear when sample, size is small. In this note, an exact confidence and an approximate confidence interval, which were recommended by Santner et al. (2007) and Lee (2006b), respectively, are compared in terms of the coverage probability and the expected length.

A Comparison of Instruction Effectiveness between the Experiment of Precipitation and the Experiment with Ball and Stick Model Related to 'Law of Definite Proportions' (일정성분비의 법칙에 관련된 앙금생성실험과 모형실험수업의 효과 비교)

  • Paik, Seoung-Hey;Kim, Hyeong-Sam;Han, Yu-Haw;Kim, Seoung-Hey
    • Journal of the Korean Chemical Society
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    • v.54 no.3
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    • pp.338-349
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    • 2010
  • This study compared the instruction effectiveness between experiments of precipitation and a ball & stick model related to the 'Law of Definite Proportions' of 9th grade science in this study. The subjects were 250 students in the 9th grade. They were divided into two groups, an experimental group and a model group. The results showed that the ratio of thought in which the elements were divided in the solutions and the ratio of thought in which a new compound was created when the two solutions were mixed were higher in the precipitation experiment group than in the model group. The two groups were not different in terms of the ratio of thought related to the reason for the creation of the precipitate. The ratio of thought pertaining to incorrect answers was high, implying that the two strategies were not effective in correcting students' thoughts. However, the ratio of finding patterns from the measuring data in the model group was higher than in the experimental group. However, the ratios of 'definite proportions' inference in the bonding of the reactants were similar in the two groups. From these data, we concluded that the inference of the 'Law of definite proportion' from experiments or models was not suitable for middle school students.

Immunohistochemical study on the atretic and the growing follicles after experimental superovulation in rats 2. Atresia and growing of follicles (과배란 유기된 rat 난소에 퇴축난포와 성장난포에 대한 면역조직화학적 연구 2. 동원된 난포의 퇴축과 성장에 대하여)

  • Kwak, Soo-dong;Koh, Phil-ok;Kim, Chong-sup
    • Korean Journal of Veterinary Research
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    • v.37 no.1
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    • pp.79-86
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    • 1997
  • This study was designed to investigate the effects of superovulation on the growing and mature follicles following gonadotrophin treatments in mature rat by immunohistochemical methods. Eighteen mature rats (Sprague-Duwely, 190~230gm) were randomly alloted into 3 groups. One group was control group, another FSH-treated group was injected intramuscularly with 0.5 units of follicular stimulating hormone(FSH) / rat, and third PMS and HCG-treated group was injected intramuscularly with 20~25IU of pregnant mare serum(PMS) / rat and then at the 48 hrs later, with 20~25IU of human chorionic gonadotropin(HCG) / rat. Half the number of rats were administrated intraperitoneally with bromodeoxyuridine(Brdur, 0.2mg/gm BW once) at 2 hours before exanguination and the remainder of rats were sacrified without Brdur administration. The investigation by immunohistochemical methods using paraffin sections of ovaries was performed by using anti-Brdur antibody and PCNA(proliferating cell nuclear antigen) antibody for labeling proliferating cells in follicles. In immunohistochemical findings, follicles squeezed by peripheral corpus luteum or follicles large follicles with loosly and irregularly distributed granulosa cells and although with compacted granulosa cells, middle follicles with dilated round or oval follicular antrum were confirmed as atretic follicles. The proportions of atretic follicles in control group were 29.8%, 21.7% and 14.2% respectivley at large, middle and small follicles and mean proportions of these all 3 grade follicles were 26.7%. The proportions of atretic follicles in FSH-treated group were 35.4%, 24.9% and 10.4% respectively at large, middle and small follicles and mean proportions of these all 3 grade follicles were 28.1%. The proportions of atretic follicles in PMS and HCG-treated group were 44.7%, 24.0% and 12.7% respectively at large, middle and small follicles, and mean proportions of these all 3 grade follicles were 29.7%. The above findings reveal that the group with higher proportion of atretic follicles were ordered as large, middle and small follicles in size, and these proportions were increased in hormone treated two groups with more number of more growing and mature follicles when compared with control group.

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