• Title/Summary/Keyword: Stratified sample mean

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Weighted Hot-Deck Imputation in Farm and Fishery Household Economy Surveys (농어가경제조사에서 가중핫덱 무응답 대체법의 활용)

  • Kim Kyu-Seong;Lee Kee-Jae;Kim Jin
    • The Korean Journal of Applied Statistics
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    • v.18 no.2
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    • pp.311-328
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    • 2005
  • This paper deals with a treatment of nonresponse in farm and fishery household economy surveys in Korea. Since the samples in two surveys were selected by stratified multi-stage sampling and weighted sample means has been used to estimate the population means, we choose a weighted hot-deck imputation method as an appropriate method for two surveys. We investigate the procedure of the weighted hot-deck as well as an adjusted jackknife method for variance estimation. Through an empirical study we found that the method worked very well in both mean and variance estimation in two surveys. In addition, we presented a procedure of forming imputation class and formed four imputation classes for each survey and then compared them with analysis. As a result, we presented two most efficient imputation classes for two surveys.

A Study on the Brand Positioning by the New Generation's Consciousness of Fashion (신세대의 패션의식에 따른 상표 포지셔닝 연구)

  • 박은순;이은경
    • Journal of the Korean Society of Costume
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    • v.44
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    • pp.201-213
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    • 1999
  • In this study, an attempt was made to classify the new generation by the conciousness of fashion and to make out positioning map, for brands of which each of the classified groups were aware. It's also intended to show a strategy brand marketing strategy by comparing the attribues that they considered important. The subjects of this study were gatheres into stratified sample groups from women whose age were ranged from 18 to 24 in Taejon. The subject brands of this study were Nice Claup. Y'sb. SYSTEM. i.n.v.u. On & On. EnC. ZOOC and Tomboy. which were selected because of high awareness. The results of this study were as below: 1. The new generation was grouped into a individuality-oriented group and an utility-oriented group. 2. As a result of analyzing brand image similarity, it's found that each group perceived the similarity differently. The individuality-oriented group perceived brand differentially more than the utility-oriented group. 3. concerning brand image preference, the individuality-oriented group preferred EnC most in light of self-expression and fashion, and preferred ZOOC most in view of utility. What was most preferred by the utility-oriented group was EnC in view of fashion and quality and ZOOC in the aspect of fashion, quality, price and design. 4. Regarding satisfaction level at brand image attributes, both of the groups showed satisfaction at On & On and Y'sb in light of self-expression. The individuality-oriented group was contented with SYSTEM's price and Nice Claup's utility and quality. 5. As a result of analyzing the groups' demographic variables, age and monthly mean income made a significant difference.

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Effect of Hydronephrosis on Survival in Advanced Stage Cervical Cancer

  • Goklu, Mehmet Rifat;Seckin, Kerem Doga;Togrul, Cihan;Goklu, Yasemin;Tahaoglu, Ali Emre;Oz, Murat;Ertas, Ibrahim Egemen
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.10
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    • pp.4219-4222
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    • 2015
  • Background: Hydronephrosis is frequently encountered in advanced stage cervical cancers, and may be associated with mortality. In the present study, we aimed to demonstrate the effect of hydronephrosis on survival in patients with inoperable advanced stage cervical cancer. Materials and Methods: The study data were acquired by retrospective analysis of the patient records belonging to 165 women with FIGO (International Federation of Gynecology and Obstetrics) stage-IIIB or more advanced cervical cancer, which were not surgical candidates. Parameters including patient age, pathological diagnosis, disease stage, pelvic sidewall extension, presence of hydronephrosis and administration of chemoradiation were analyzed. Further, the effects of these variables on survival were assessed. P values less than 0.05 were considered statistically significant. Results: The distribution of the study patients according to disease stage was as follows: 131 (79.4%) had stage-IIIB, 18 (10.9%) had stage-IVB and 16 (% 9.7) patients had stage-IVA disease. Hydronephrosis was not evident in 91 (55.2%) of these patients, whereas 41 (24.8%) had unilateral and 33 (20%) patients had bilateral hydronephrosis. When compared to mean survival in patients who did not have hydronephrosis, survival was significantly shortened in patients who had bilateral and unilateral hydronephrosis (p<0.05). There was no significant survival difference between patients with unilateral and bilateral hydronephrosis (p>0.05). Although patient age, pathological type, pelvic involvement, and chemotherapy treatment rates were similar (p>0.05), radiotherapy requirement rate and disease stage were significantly different among the study groups (p<0.05). Conclusions: Hydronephrosis was found to be a significant predictor of poor survival in patients with advanced stage cervical cancer, irrespective of unilateral or bilateral involvement.While waiting for future studies with larger sample sizes, we believe that the FIGO stages in advanced cervical cancer could further be stratified into subgroups according to presence or absence of hydronephrosis.

A Study about Promoting Health Lifestyles and Relating Variables on the Life-cycle of women (여성들의 생애주기별 건강증진행위와 관련요인에 관한 연구 - 일개 통합시를 중심으로 -)

  • 이은희;소애영;최상순
    • Journal of Korean Academy of Nursing
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    • v.29 no.3
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    • pp.700-710
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    • 1999
  • Promoting women's health lifestyles are important due to their connection to family health. The purpose of this study was to analyse women's health lifestyles(HPL) and their effects on women's life-cycle, so in order to develop a program in a women's health care center. The subjects included were 1080 women over 18 years old living in Wonju city, and were selected by stratified and purposive sampling. The data were collected through a questionnaire and interview. The Cronbach $\alpha$, %, mean, ANOVA, Pearson's correlation, and regression in SPSS PC Win. package was used to analyze the data. The sample was sepernted into three groups premarital group 20.2%(premarital women between 18 and 40 years old), delivery and children rearing group 49.9%(marital women between 18 and 40 years old), over middle agedelderly group 29.9%(women over 41 years old). Significant difference were found in the HPL according to group. Also, relating variables, such as self-efficacy, family functions, health locus of control and gender role perception that were considered relating variables to HPL significantly differed among the three groups. HPL significantly correlated with self-efficacy, family functions, HLOC and gender role perception in all participants and at all groups. The regression analysis of HPL was interpreted 40.6% with relating variables, self-efficacy, health attention, family functions, and internal locus of control, health perception, power other locus of control and chance locus of control in all participant. Self-efficacy, family functions, health attention were considered important variables in premarital group, self-efficacy, family functions, internal locus of control, health attention, health perception and power of control were important in delivery-rearing group. Self-efficacy, health attention, internal locus of control, family functions and health perception were important in middle aged-elderly group. As a result, we found the differences HPL scores and relating variables according to life-cycle groups. Therefore, we should prepare health promoting education programs for women according to women's life cycles. Also we suggest that women's health care centers based on communities was needed for proper management of women's health.

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The Impacts of Difficulty on Daily Activities, Grip Strength, and Activities of Daily Living on Perceived Health in Community-living Older Adults (재가노인의 일상활동 어려움, 악력, 일상생활동작이 주관적 건강에 미치는 영향)

  • HongSon, Gwi-Ryung;Lee, Yoon-Kyoung;Park, Young-Sun;Oh, Eun-Mi
    • Journal of muscle and joint health
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    • v.17 no.2
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    • pp.192-202
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    • 2010
  • Purpose: The purpose of the study was to examine the predictive relationships between predictors [(difficulty on daily activities due to arthritis, falls, and pain, grip strength, and activities of daily living (ADLs)], and perceived health in community-living older adults in Korea. Method: A descriptive, cross-sectional survey design was used. Data were obtained from Korean Longitudinal Study of Ageing conducted in 2006. A stratified sample was selected of 5,545 older adults who were over 60 years old for analysis of this study. Descriptive statistics, t-test, Pearson's correlations, and multiple regressions were used. Result: Mean age was 70.27 years (SD=7.27) ranged from 60 and 105 years old. Perceived health was significantly associated with grip strength, and ADL. With multiple regression, all main variables explained 22.1% for perceived health. Difficulty on daily activities due to pain was the strongest predictor on perceived health. Grip strength, ADLs, gender, and difficulty on daily activities due to arthritis and falls were also significant predictors on perceived health. Conclusion: When developing nursing intervention to improve perceived health in older adults, their difficulties on daily activities, grip strength, and ADLs should be assessed.

Significance of Follow-Up Ultrasonography 24 Hours Post-Reduction in Detecting Intussusception Recurrence

  • Kim, Sujin;Lim, HyeJi;Park, Sowon;Koh, Hong
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.25 no.1
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    • pp.21-29
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    • 2022
  • Purpose: The objective of this study was to identify the significance of 24-hour post-reduction ultrasonography (US) in pediatric patients with intussusception. Methods: A total of 229 patients with intussusception who were treated with saline reduction at Severance Children's Hospital between January 2014 and September 2020 were retrospectively reviewed. The 229 patients with successful saline reduction were divided into two groups: a recurrence at 24 hours group (R, n=41) and a non-recurrence group (NR, n=188). The full patient sample was divided into two groups: follow-up US (FU) or no follow-up US (NFU); the recurrence group was divided into follow-up (R-FU) and non-follow-up (R-NFU) subgroups, and stratified analyses were performed. Results: There were no significant differences in age, sex, laboratory findings, symptoms, and sonographic findings between the NR and R groups. In the R group, 24 patients underwent follow-up US, and 17 patients did not. Specific sonographic findings were statistically significant in the R-FU group compared to the R-NFU group (p=0.002). The R-FU group had fewer admissions (p=0.012) and longer mean hospitalization times (p<0.001) than the R-NFU group. The NFU group had a 12.2% recurrence rate, while the R-FU group recurrence rate was 25.8% (p=0.0099), suggesting that the omission of some recurrent events and follow-up US was a significant variable in the recurrence of intussusception. The median time to recurrence was 21 hours which supports the 24-hour follow-up protocol. Conclusion: Twenty-four-hour follow-up US was shown to be valuable for detecting early recurrence of intussusception.

Information Needs of Prisoners and Adequacy of Information Resources in Prison Libraries in Anambra State, Nigeria

  • Obiora Kingsley Udem;Oluoma Miracle Emereonwu;Chisom Marycynthia Nwadibe
    • International Journal of Knowledge Content Development & Technology
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    • v.14 no.3
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    • pp.19-38
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    • 2024
  • This study investigated the information needs of prisoners and the adequacy of information resources in prison libraries in Anambra State, Nigeria. Two research questions guided the study. The population of the study was 1781 inmates in prisons in Anambra State. The sample size of 327 was selected using Taro Yamane's formula and proportionate stratified sampling techniques. Two instruments titled the Information Needs of Prisoners Questionnaire and the Adequacy of Information Resources Checklist were used for data collection. The instruments were validated by three experienced lecturers. One in the department of Educational Foundations (Measurement and Evaluation Unit) and two in the Department of Library and Information Science, all at Nnamdi Azikiwe University, Awka. Cronbach's alpha was used to determine the internal consistency of the questionnaire items, with a value of 0.79. The researchers administered the questionnaires with the help of four research assistants (correctional officers). Out of 327 questionnaires administered, 314 were successfully retrieved. The percentage return rate of distributed questionnaires is 96%. Data collected were analyzed using descriptive statistics of the mean; also, the International Federation of Library Association (IFLA) guideline for library services to prisoners was also used as a yardstick for the measurement of adequacy. The results from the data analysis indicated that prisoners have diverse information needs that, when met, would help them during their stay in prison as well as when they are eventually released; these needs include legal information, information on prison rules, financial information, and others. While there were few information resources found to be adequate, the inadequacy of most of the listed information resources is recorded in prison libraries in Anambra State, Nigeria. It is therefore recommended that information resources be made adequately available for prisoners in relation to their information needs.

A Study on the Estimation of the Stock Density and Biomass of Perinereis aibuhitensis at the Tidal Zone in Sosan, Korea (서산 연안간석지에서 두토막눈썹참갯지렁이(청충), Perinereis aibuhitensis의 분포밀도와 현존자원량의 추정)

  • KIM Chong-Kawn;ZHANG Chang-Ik
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.24 no.4
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    • pp.229-236
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    • 1991
  • A study on the estimation of the stock density and biomass of Perinereis aibuhitensis in the tidal zone in Sosan, Chungchongnam-do, Korea was carried out from June to July 1988. A preliminary survey was conducted to determine the distribution pattern of the species and the optimum sample size for setting up the sampling design. The stock densities of the species by stratum and by subarea were estimated using the stratified random sampling method, based upon the results of preliminary survey. The differences in density between strata as well as among subareas were tested to decide whether they can be combined together for estimating the overall stock biomass or not. The results of the survey showed that p. aibuhitensis were randomly distributed(Poisson distribution) and the number of quadrats which satisfies a reasonable level of precision was determined to be five by stratum. The densities between strata were not significantly different, while densities among subareas were different. Subarea C showed the highest density with the mean of $53.9g/m^2$ and followed by subarea B. The density of subarea A was the lowest with the mean of $18.2g/m^2$. The overall mean density from the study area was $32.4g/m^2$ with the coefficient of variance(CV) of $6.8\%$ The overall stock biomass was estimated to be 147.5mt in this area.

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Survival Analysis for White Non-Hispanic Female Breast Cancer Patients

  • Khan, Hafiz Mohammad Rafiqullah;Saxena, Anshul;Gabbidon, Kemesha;Stewart, Tiffanie Shauna-Jeanne;Bhatt, Chintan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.9
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    • pp.4049-4054
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    • 2014
  • Background: Race and ethnicity are significant factors in predicting survival time of breast cancer patients. In this study, we applied advanced statistical methods to predict the survival of White non-Hispanic female breast cancer patients, who were diagnosed between the years 1973 and 2009 in the United States (U.S.). Materials and Methods: Demographic data from the Surveillance Epidemiology and End Results (SEER) database were used for the purpose of this study. Nine states were randomly selected from 12 U.S. cancer registries. A stratified random sampling method was used to select 2,000 female breast cancer patients from these nine states. We compared four types of advanced statistical probability models to identify the best-fit model for the White non-Hispanic female breast cancer survival data. Three model building criterion were used to measure and compare goodness of fit of the models. These include Akaike Information Criteria (AIC), Bayesian Information Criteria (BIC), and Deviance Information Criteria (DIC). In addition, we used a novel Bayesian method and the Markov Chain Monte Carlo technique to determine the posterior density function of the parameters. After evaluating the model parameters, we selected the model having the lowest DIC value. Using this Bayesian method, we derived the predictive survival density for future survival time and its related inferences. Results: The analytical sample of White non-Hispanic women included 2,000 breast cancer cases from the SEER database (1973-2009). The majority of cases were married (55.2%), the mean age of diagnosis was 63.61 years (SD = 14.24) and the mean survival time was 84 months (SD = 35.01). After comparing the four statistical models, results suggested that the exponentiated Weibull model (DIC= 19818.220) was a better fit for White non-Hispanic females' breast cancer survival data. This model predicted the survival times (in months) for White non-Hispanic women after implementation of precise estimates of the model parameters. Conclusions: By using modern model building criteria, we determined that the data best fit the exponentiated Weibull model. We incorporated precise estimates of the parameter into the predictive model and evaluated the survival inference for the White non-Hispanic female population. This method of analysis will assist researchers in making scientific and clinical conclusions when assessing survival time of breast cancer patients.

Statistical Estimates from Black Non-Hispanic Female Breast Cancer Data

  • Khan, Hafiz Mohammad Rafiqullah;Ibrahimou, Boubakari;Saxena, Anshul;Gabbidon, Kemesha;Abdool-Ghany, Faheema;Ramamoorthy, Venkataraghavan;Ullah, Duff;Stewart, Tiffanie Shauna-Jeanne
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.19
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    • pp.8371-8376
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    • 2014
  • Background: The use of statistical methods has become an imperative tool in breast cancer survival data analysis. The purpose of this study was to develop the best statistical probability model using the Bayesian method to predict future survival times for the black non-Hispanic female breast cancer patients diagnosed during 1973-2009 in the U.S. Materials and Methods: We used a stratified random sample of black non-Hispanic female breast cancer patient data from the Surveillance Epidemiology and End Results (SEER) database. Survival analysis was performed using Kaplan-Meier and Cox proportional regression methods. Four advanced types of statistical models, Exponentiated Exponential (EE), Beta Generalized Exponential (BGE), Exponentiated Weibull (EW), and Beta Inverse Weibull (BIW) were utilized for data analysis. The statistical model building criteria, Akaike Information Criteria (AIC), Bayesian Information Criteria (BIC), and Deviance Information Criteria (DIC) were used to measure the goodness of fit tests. Furthermore, we used the Bayesian approach to obtain the predictive survival inferences from the best-fit data based on the exponentiated Weibull model. Results: We identified the highest number of black non-Hispanic female breast cancer patients in Michigan and the lowest in Hawaii. The mean (SD), of age at diagnosis (years) was 58.3 (14.43). The mean (SD), of survival time (months) for black non-Hispanic females was 66.8 (30.20). Non-Hispanic blacks had a significantly increased risk of death compared to Black Hispanics (Hazard ratio: 1.96, 95%CI: 1.51-2.54). Compared to other statistical probability models, we found that the exponentiated Weibull model better fits for the survival times. By making use of the Bayesian method predictive inferences for future survival times were obtained. Conclusions: These findings will be of great significance in determining appropriate treatment plans and health-care cost allocation. Furthermore, the same approach should contribute to build future predictive models for any health related diseases.