• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.159-164
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• 2019

The statistical inference of Cronbach's alpha measure of internal reliability is known to be inaccurate when sample size is small and the assumption of normality is violated. In this paper, we describe the permutation method in which we compute resampling p-values for testing the difference between two or more independent Cronbach's alpha coefficients. When the over-all permutation test is significant, we also make pairwise post-hoc comparisons using permutaion method. The permutation tests for the equality of two independent Cronbach's alpha coefficients and three independent Cronbach's alpha coefficients are illustrated with an example analysis of survey data.

• Journal of the Korea Society of Computer and Information
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• v.28 no.5
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• pp.179-187
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• 2023

In this paper, we studied the impact of outliers on the power of the significance tests for Cronbach alpha reliability coefficient. Four variables were varied: sample size, the number of items, the number of outliers and population Cronbach Alpha levels. We simulated data using multivariate normal distribution and used outliers sampled from uniform distribution. To test the significance of Cronbach Alpha Reliability, parametric approach(F statistic) and permutation method were used. Consequently, we observed that the powers of permutation test are equal to or greater than those of F test under all conditions, and also both F test and permutation test lose the power as the number of outliers increases, and that these effects of outliers on the power are enhanced for increasing population alpha levels.

• The Korean Journal of Applied Statistics
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• v.34 no.1
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• pp.1-8
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• 2021

Abstract concepts in social research must use measurement tools that are assured of validity and reliability. Observation score derived by a measurement tool can be divided into a valid observation score, a biased observation score, and an error. The presence or absence of a biased value is associated with validity, and the presence or absence of an error value is associated with reliability. There are many techniques for seeing whether a measurement tool is valid and reliable. For example, there are construct validity using factor analysis and internal consistency based on the Cronbach alpha. In this study, the calculation of the Cronbach alpha is derived through a sample, so we suggest an estimator of the Cronbach alpha under complex sample design and nonresponse. In a simulation, the proposed method is compared with many other existing estimators of Cronbach alpha under a multivariate normal distribution.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.701-705
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• 2011

The paper reviews Cronbaha's coefficient to measure a single source of error. On the contrary to classical measurement theory, the generalizability study can be used in the social survey design to calculate Generalizability Index (GI) and Dependability Index (DI) for measuring multiple sources of errors of behavior evaluation. The study proposes application guidelines to implement R:($A{\times}B$) mixed models that are composed of random factor and fixed factor.

• Journal of Chest Surgery
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• v.48 no.2
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• pp.112-119
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• 2015

Background: Pectus excavatum (PE) is the most common chest wall deformity. The Nuss Questionnaire modified for Adults (NQmA) is a disease-specific health-related quality of life assessment tool for patients with pectus deformities. The aim of this study is to adapt the NQmA into Turkish. Methods: Two hundred and sixty-five patients with PE were participated, with an age range of 14 to 29 years. All patients underwent a physical examination and had not undergone corrective surgery. The Turkish version of the NQmA was completed by patients and their parents. Results: The content validity index based on expert opinions was 91% for the patient questionnaire and 96% for the parent questionnaire. The Cronbach's alpha value for the NQmA was found to be 0.805 for the patient questionnaire and 0.800 for the parent questionnaire. Exploratory factor analysis was used to assess construct validity. Two factors explained 51.1% of the total variance in the patient questionnaire (psychosocial: 31.145%, Cronbach's alpha=0.818; physical: 19.955%, Cronbach's alpha=0.862). In the parent questionnaire, two factors explained 51.422% of the total variance (psychosocial: 26.097%, Cronbach's alpha=0.743; physical: 25.325%, Cronbach's alpha=0.827). Construct validity was confirmed by confirmatory factor analysis. Conclusion: The Turkish version of the NQmA was found to be valid and reliable for the assessment of quality of life in patients with PE.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.222-228
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• 2008

Purpose: The objectives of this study were to compare the left ventricle ejection fraction (LVEF) from gated cardiac blood pool scan (GCBP) for analysis auto-drawing region of interest mode (AROI) and manual-drawing region of interest mode (MROI), respectively. To evaluation the relationships between values produced by both ROI modes. Materials and Methods: Gated cardiac blood pool scan using in vivo method Tc-99m Red Blood Cell were performed for 33 patients (mean age: $53.2{\pm}13.2\;y$) with objective of chemotherapy using single head gamma camera (ADAC Laboratories, Milpitas, CA). Left ventricular ejection fraction was automatically and manually measured, respectively. Results: There was significant difference statistically between AROI and MROI ($LVEF^{AROI}$: $71.4{\pm}12.4%$ vs. $LVEF^{MROI}$: $65.8{\pm}5.9%$, p=0.003). Intra-observer agreements in AROI was higher than MROI ($\gamma^{AROI}=0.964$, Cronbach's $\alpha^{AROI}=0.986$ vs. $\gamma^{MROI}=0.793$, Cronbach's $\alpha^{MROI}=0.911$), either. Additionally, there was no significant difference statistically at best septal view (${\Delta}LVEF^{BSV}=0.7{\pm}2.3%$, p=0.233), however statistically significant difference was found at badly separated septal view (${\Delta}LVEF=10.9{\pm}11.4%$, p=0.001). Moreover, Intra-observer agreements in best septal view was higher than badly separated septal view ($\gamma^{BSV}=0.939$, Cronbach's $\alpha^{BSV}=0.978$; $\gamma=0.948$, Cronbach's $\alpha=0.981$ at AROI, $\gamma^{BSV}=0.836$, Cronbach's $\alpha^{BSV}=0.936$; $\gamma=0.748$, Cronbach's $\alpha=0.888$ at MROI). Conclusion: When best septal view was acquired, LVEF by AROI and MROI indicated not different. Comparing Intra-observer agreements with AROI and MROI, the AROI tended to show higher. Therefore, it is considered that the AROI than MROI is valuable in reproducibility and objective when ROI analysis by acquire left ventricular of best septal view.

• Journal of Acupuncture Research
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• v.22 no.3
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• pp.271-280
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• 2005

Objective : The aim of this study is to evaluate internal reliability and correlation among assessment instruments of knee OA. Methods : Data were obtained from 85 patients with knee OA. They were asked to answer VAS pain scale, two disease-specific questionnaires (WOMAC and LFI) and one instrument about health-related quality(KHAQ). Reliability was assessed using cronbach`s alpha. Correlation was assessed by examining the pearson`s correlation coefficients. Results : Cronbach`s alpha of all Index except WOMAC stiffness subscale.(6679) exceeded the value of 0.70. A good correlation was obtained between WOMAC Subscales (especially Pain Subscale) and LFI (.726

• Journal of Korean Physical Therapy Science
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• v.18 no.3
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• pp.53-61
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• 2011

Purpose : his study was to analyze the reliability and validity on Oswestry Low Back Pain Disability Index (OLBPDI) in patients with low back pain. Methods : The sample consisted of 211 patients who had received treatments at the physical therapy units of 3 medical institutions from February to December 2008 in Andong city. Questionnaires on the OLBPDI were recruited by 6 physical therapists. The internal structure and reliability of the scales were evaluated by means of item-internal consistency(Cronbach's alpha coefficient:${\alpha}$), item-discriminant validity, Pearson's relation coefficient. Results : An average of patients's age was 41.1 years. The range of OLBPDI subscales were .93~.94 in Cronbach's ${\alpha}$. The internal consistency reliability of total item-each item were also internally consistent with Cronbach's ${\alpha}$ range of .94~.95(Pearson's correlation coefficient range: .62~.89). However, high correlation were obtained among 10 items(.67~.83), therefore the item-discriminant validity was a little low. Conclusion: In conclusion, the results reported here confirm the reliability of the OLBPDI scales in patients with low back pain. The collection of information on the level of disability due to low back pain using this instrument was acceptable to patients. A further prospective multi-center study will be necessary to prove the reliability and validity.

• Korean Journal of Child Studies
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• v.19 no.1
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• pp.183-192
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• 1998

The purpose of this study was to develop an assessment scale of the profile of kindergarten teachers. The subjects were 287 kindergarten teachers. Data were collected from June to September in 1997. Construct validity and reliability were analyzed using factor analysis and Cronbach Coefficient Alpha. Factors were extracted in the order of: characteristic traits, professional knowledge, specialized function, knowledge of liberal arts, cognizance of professionalism, and occupational consciousness. The Cronbach Coefficient Alpha of the selected 30-item assessment scale was .9068.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.9 no.2
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• pp.198-208
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• 1998

The purpose of this study was to develop a 'Korean Child Rearing Attitudes Inventory', in order to understand the effects of parents rearing attitudes on social phobia. The total subjects were 392 high school students in Seoul. The scales wwereadministered to the subjects and we examined the reliability and validity. The results were as follows. According to the factor analysis, six factors abstracted from the father's rearing attitudes：rejection, high expectation, anxious, control, emotional care and overconcern of other's opinion. By the method of reliability analysis and factor analysis, finally selected items were 60. The reliability of the factors ranged from .76 to .90 by Cronbach ${\alpha}$. Five factors abstracted from the mother's rearing attitudes：anxious, high expectation, rejection, emotional care and overconcern of other's opinion. And total selected items of mother's rearing attitudes were 61. The reliability of the factors ranged from .72 to .91 by Cronbach ${\alpha}$. The construct validity and reliability of this inventory were supported.