• Korean Journal of Human Ecology
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• v.6 no.1
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• pp.89-96
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• 1997

The purpose of this study was to determine the clothing value, awareness of and concern about clothing's country of origin in Korea and England university women. University women in Korea and England were surveyed to determine the importance attributed to 32 descriptors defining 8 clothing values. Awareness of, and concern about, clothing's country of origin were determined mean-scores, t-test and $x^2$-analyses were done. A different rank order of importance for clothing values exists for both groups. The Korea sample rated aesthetic, economic, theorical, political, exploratory and sensory significantly higher and social, religious significantly lower than England sample. England sample appeared to be more aware, concerned about clothing's country of origin than Korea sample. More Korea women were able to recall country of origin. Over half Korea sample but less than 22% England sample recalled purchasing primarily domestic apparel.

• Communications for Statistical Applications and Methods
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• v.19 no.3
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• pp.405-414
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• 2012

In a stratified sample, the sampling frame is divided into non-overlapping groups or strata (e.g. geographical areas, age-groups, and genders). A sample is taken from each stratum, if this sample is a simple random sample it is referred to as stratified random sampling. In this paper, we study the bootstrap inference (including confidence interval) and test for a stratified population mean. We also introduce the bootstrap consistency based on limiting distribution related to the plug-in estimator of the population mean. We suggest three bootstrap confidence intervals such as standard bootstrap method, percentile bootstrap method and studentized bootstrap method. We also suggest a bootstrap test method computing the $ASL_{boot}$(Achieved Significance Level). The results of estimation are verified using simulation.

• Biomedical Science Letters
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• v.14 no.2
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• pp.105-113
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• 2008

The objective of this study was to evaluate the influence of surface modifications on the bonding characteristics and cytotoxicity of specific titanium porcelain bonded to milling titanium and cast titanium. Milling titanium and cast titanium samples were divided into 8 test groups. These groups are as follow: i) sandblasted with particles of different size of $220{\mu}m\;and\;50{\mu}m$, ii) different sequences of sandblasting treatment and etching treatment, iii) etched with different etching solutions, and iv) preheated or not. The surface characteristics of specimens were characterized by the test of mean roughness of surface and SEM. The bond strength of titanium-ceramic systems was measured by using three-point bending test and SEM. The results show that the mean roughness of surface of sample sandblasted with $220{\mu}m$ aluminum oxide increased and bond strength were higher than sample sandblasted with $50{\mu}m$ aluminum oxide. The mean roughness of surface decreased, but the bond strength increased when the samples sandblasted with $220{\mu}m$ aluminum oxide were preheated. The sample sandblasted with $220{\mu}m$ aluminum oxide after oxidized with occupational corrosive agent I (50% NaOH, 10% $CuSO_4{\cdot}5H_2O$) and II (35% $HNO_3$, 5% HF) showed higher bond strength than sample oxidized with 30% $HNO_3$ after sandblasted with $220{\mu}m$ aluminum oxide. Group NaCuNF220SP (milling Ti: 35.3985 MPa, casting Ti: 37.2306 MPa) which was treated with occupational corrosive agent I (50% NaOH, 10% $CuSO_4{\cdot}5H_2O$) and II (35% $HNO_3$, 5% HF), followed by sandblasting with $220{\mu}m$ aluminum oxide and preheating at $750^{\circ}C$ for 1 hour showed the highest bond strength and significant differences (P<0.05). The method for modifying surface of titanium showed excellent stability of cells.

• Proceedings of the Korean Association for Survey Research Conference
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• 2002.11a
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• pp.255-274
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• 2002

We classify rotation sampling designs into two classes. The first class replaces sample units within the same rotation group while the second class replaces sample units between different rotation groups. The first class is specified by the three-way balanced design which is a multi-level version of previous balanced designs. We introduce an extended generalized composite estimator (EGCE) and derive its variance and mean squared error for each of the two classes of design, cooperating two types of correlations and three types of biases. Unbiased estimators are derived for difference between interview time biases, between recall time biases, and between rotation group biases. Using the variance and mean squared error, since any rotation design belongs to one of the two classes and the EGCE is a most general estimator for rotation design, we evaluate the efficiency of EGCE to simple weighted estimator and the effects of levels, design gaps, and rotation patterns on variance and mean squared error.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.76-83
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• 1999

Solid phase microextraction (SPME) was used for the determination of 6 standard solvents (methanol, isopropanol, methyl ethyl ketone, ethyl acetate, cyclohexane, toluene) in food packaging materials. SPME method is a solvent-free sample preparation technique in which a fused silica fiber coated with polymeric organic liquid is introduced into the headspace above the sample. SPME method using fiber coated polydimethylisiloxane (PDMS) was compared with static headspace (SHS) method used as a reference. It was found that the optimal adsorption condition using PDMS-SPME method was 2$0^{\circ}C$ for 15 minutes for the standard solvents. Detection limits, linearity, reproducibility and recovery of both SHS and PDMS-SPME methods have been determined using 6 standard solvents. Both methods were characterized by high reproducibility and good linearity. Using SHS methods, the mean recovery of the 6 standard solvents was ranged from 75.5% to 105.8% with a mean relative standard deviation (RSD) of 0.3% to 4.8%. With PDMS-SPME method, the mean recovery of the 6 standard solvents was ranged from 86.7% to 108.3% with a mean RSD of 0.4% to 2.5%. The detection limits of both methods were the same for toluene, cyclohexane and methyl ethyl ketone; those of PDMS-SPME method were higher than those of SHS method for methanol, isopropanol and ethyl acetate. PDMS-SPME fiber shoed excellent adsorption for non-polar solvents such as toluene, while it showed relatively low adsorption for polar solvents such as methanol.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1103-1118
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• 2009

When we wish to estimate the mean or total of a finite population, the numbering of the population units is of importance. In this paper, we have proposed two methods for estimating the mean or total of a population having a linear trend, for the case when the reciprocal of the sampling fraction is an even number and the sample size is an odd number. The first method involves drawing a sample by using a method which is a generalization of Singh et al's (1968) modified systematic sampling, and using interpolation in determining the estimator. The second method involves selecting a sample by modified systematic sampling, and estimating the population parameters by the regression estimation method. Under the criterion of the expected mean square error based on Cochran's (1946) infinite superpopulation model, the proposed methods have been compared with existing methods. We have also made a comparison between the two proposed methods.

• Biomedical Science Letters
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• v.16 no.4
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• pp.311-316
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• 2010

We studied a comparison of the concentration of biochemical markers in sera of patients hospitalized with high fever (n=296) in Jeonbuk province during the last 2 years (2008 to 2009). The patients were divided into three patient groups of viral hemorrhagic fever (VHF) patient group tested positive for Hantavirus (n=53), leptospirosis (LEP) patient group tested positive for Leptospira interrogans (n=137) and scrub typhus (TSU) patient group tested positive for Orientia tsutsugamushi (n=106). We analyzed the concentration of ALP, AST, ALT, blood urea nitrogen, creatinine and glucose and compared the mean levels of them to normal range, the first sample and last sample. The frequencies of abnormal patient elevated above the upper limit of normal for ALP, AST and ALT were 18~43.4%, 78~97% and 62.3~92.7% in patient groups, and 24.5~47.4% (total protein) and 13.2~50.0% (albumin) of patients in patient groups had decreased below the lower limit of normal. The patients showed higher abnormal levels of glucose in patient groups were 58.5% (viral hemorrhagic fever patient group), 66.4% (leptospirosis patient group), 71.7% (scrub typhus patient group) and 66.9% (total patient group). There were significant difference between the first sample and the last sample in the mean levels of AST (decreased 22.2% in viral hemorrhagic fever patient group, 30.2% in leptospirosis patient group, 20.4% in scrub typhus patient group and 24.1% in total patient group), BUN (43.0% in viral hemorrhagic fever patient group, 41.6% in leptospirosis patient group, 47.4% in scrub typhus patient group and 43.0% in total patient group) and glucose (20.2% viral hemorrhagic fever patient group, 17.9% in leptospirosis patient group, 18.6% in scrub typhus patient group and 18.9% in total patient group) in the first sample and the last sample. According to these results, those diseases may cause liver damage and have high concentration of ALP, AST, ALT and glucose in blood even though the patients get out of the hospital.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.399-406
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• 1996

Acidic fog is catastrophic to aviation and potentially affect materials, vegetation, crops and public health. This paper was carried out to investigate the chemical features of fog sample at Mt. Sobaek (mean sea level : 1, 340m) from June to August 1995. Each sample was analyzed for pH, electrical conductivity and major ions (anion : $Cl^N)_3^-, SO_4^{2-}, cation : Na^+, NH_4^+, K^+, Mg^{2+}, Ca^{2+}$) by ion chromatography. The quality analysis of fog sample data was performed based on ion balance and electrical conductivity method. The wind directions are subdivided into the northerly and southerly wind according to the wind direction data at the Sobaek-san meteorological observation station. Statistical analyses were performed on the complete set of results in order to obtain a description of fog sample. All the statistical treatment was carried out using the SPSS/PC + software package. The major ion concentration of fog samples was higher for the northwesterly wind cases than sourtheasterly wind cases. The pH of fog sample varied between 2.95 and 6.08. The average pH and electrical conductivity of total sample (n=210) were 4.39 and 113.0 $\mu$S/cm, respectively. It may be noted that in nearly all the cases, the dominant major ions in the fog sample at Mt. Sobaek were $SO_4^{2-}, NO_3^-, H^+ and NH_4^+$.

• Women's Health Nursing
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• v.4 no.3
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• pp.375-387
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• 1998

In clinical trials of nursing research, the sample size determination is one of the most important factor. Although sample size must be considered at the design stage, it has been disregarded in most clinical trials. The power analysis is usually performed before study begins to compute sample size and the power can also be calculated at the end of study in order to justify study result. The power analysis is essential especially when the clinical trials can not show significant differences. In this paper, we review the statistical methods for power analysis and sample size formulae in nursing research. Sample size formulae and the corresponding examples are discussed according to the six types of studies ; mean for one sample, proportion for one sample, means in two samples, proportions in two samples, correlation coefficient and ANOVA.

• Journal of the Korean Statistical Society
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• v.22 no.2
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• pp.191-200
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• 1993

An asymptotic estimation problem of the unknown mean is studied under a general loss function. The proof of this result is based on the asymptotic expansion of the risk function. Also conditions for second order admissibility and minimaxity of a class of estimators depending only on the sample mean are established.