• Title/Summary/Keyword: response bias

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Effects of Psychosocial Interventions on Cortisol and Immune Parameters in Patients with Cancer: A Meta-analysis (암 환자에게 적용한 심리사회적 중재가 코티졸과 면역기능에 미친 효과: 메타분석)

  • Oh, Pok Ja;Jang, Eun-Su
    • Journal of Korean Academy of Nursing
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    • v.44 no.4
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    • pp.446-457
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    • 2014
  • Purpose: This study was done to evaluate the effects of psychosocial interventions on cortisol and immune response in adult patients with cancer. Methods: MEDLINE via PubMed, Cochrane Library CENTRAL, EMBASE, CINAHL and domestic electronic databases were searched. Twenty controlled trials (11 randomized and 9 non-randomized trials) met the inclusion criteria with a total of 862 participants. Methodological quality was assessed using the Cochrane's Risk of Bias for randomized studies and the Risk of Bias Assessment tool for non randomized studies. Data were analyzed using the RevMan 5.2.11 program of Cochrane library. Results: Overall, study quality was moderate to high. The weighted average effect size across studies was -0.32 (95% CI [-0.56, -0.07], p=.010, $I^2 $=45%) for cortisol concentration, -0.62 (95%CI [-0.96,-0.29], p<.001, $I^2 $=0%) for T lymphocyte (CD3) and -0.45 (95%CI [-0.74, -0.16], p=.003, $I^2 $=0%) for Th lymphocyte (CD4) numbers. Psychosocial interventions were not effective for Tc lymphocyte (CD4), NK cell, monocyte, and cytokine response. Conclusion: Although these results provide only small evidence of successful immune modulation, they support the conclusion that psychosocial interventions can assist cancer patients in reducing emotional distress and improving immune response.

A Weighted Mean Squared Error Approach to Multiple Response Surface Optimization (다중반응표면 최적화를 위한 가중평균제곱오차)

  • Jeong, In-Jun;Cho, Hyun-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.625-633
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    • 2013
  • Multiple response surface optimization (MRSO) aims at finding a setting of input variables which simultaneously optimizes multiple responses. The minimization of mean squared error (MSE), which consists of the squared bias and variance terms, is an effective way to consider the location and dispersion effects of the responses in MRSO. This approach basically assumes that both the terms have an equal weight. However, they need to be weighted differently depending on a problem situation, for example, in case that they are not of the same importance. This paper proposes to use the weighted MSE (WMSE) criterion instead of the MSE criterion in MRSO to consider an unequal weight situation.

A Study on Determinants Affecting At-home Laver Consumption Expenditures : Type II Tobit Model Treating Sample Selection Bias (김 가정 소비 지출의 결정 요인 분석 : 선택 편의를 고려한 Type II 토빗 모형을 이용하여)

  • Lee, Min-Kyu;Park, Eun-Young
    • The Journal of Fisheries Business Administration
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    • v.40 no.3
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    • pp.147-167
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    • 2009
  • The objective of this study is to analyze the determinants of at-home laver consumption expenditures using the data from a survey of households implemented in 2009. It happened that non-response ratios of monthly expenditures on dry laver and flavored laver among sampled households are 18.8% and 25.6%. Accordingly, this study tries to analyze the determinants affecting at-home laver consumption expenditures by using type II tobit model, one of sample selection models, to deal with sample selection bias caused from non-response data. Analysis results show the age variable positively affects expenditures on dry laver but negatively contributes to expenditures on flavored laver. In addition, the household size, the household's income, the degree of preference for laver have positive relationships with both expenditures. Household size elasticity and income elasticity of the expenditure on dry laver are estimated as 0.220 and 0.251. In the case of flavored laver, these elasticities are estimated as 0.484 and 0.261. Such analysis results can provide information on division of the at-home laver consumption market into groups with high willingness to expense and implementation of detailed marketing strategies to increase at-home laver consumption. The methodology of this study can be applied to consumer preference analysis on other marine products and other analyses on sample with non-response data in the fishery research.

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Restricted Mixture Designs for Three Factors

  • Nae K. Sung;Park, Sung H.
    • Journal of the Korean Statistical Society
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    • v.9 no.2
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    • pp.145-172
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    • 1980
  • Draper and Lawrence (1965a) have given mixture designs for three factors when all the mixture components can vary on the entire factor space so that the region of interest is an equilateral triangle in two dimensions. In this paper their work is extended to the cases when the region of interest is an echelon, parallelogram, pentagon or hexagon, because of the restirctions imposed on some or all of the mixture components. The principles used in the choice of appropriate designs are those originally introduced by Box and Draper(1959). It is assumed that a response surface equation of first order is fitted, but there is a possibility of bias error due to presence of second order terms in the true model. Minimum bias designs for several cases of restricted regions of interest are illustrated.

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A study on sensitivity of representativeness indicator in survey sampling (표본 추출법에서 R-지수의 민감도에 관한 연구)

  • Lee, Yujin;Shin, Key-Il
    • The Korean Journal of Applied Statistics
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    • v.30 no.1
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    • pp.69-82
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    • 2017
  • R-indicator (representativeness indicator) is used to check the representativeness of samples when non-responses occur. The representativeness is related with the accuracy of parameter estimator and the accuracy is related with bias of the estimator. Hence, unbiased estimator generates high accuracy. Therefore, high value of R-indicator guarantees the accuracy of parameter estimation with a small bias. R-indicator is calculated through propensity scores obtained by logit or probit modeling. In this paper we investigate the degree of relation between R-indicator and different non-response rates in strata using simulation studies. We also analyze a modified Korea Economic Census data for real data analysis.

Designs for Improving Mean Response

  • Park, Joong-Yang;Suh, Euy-Hoon;Ahn, Sung-Jin
    • Journal of Korean Society for Quality Management
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    • v.23 no.3
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    • pp.102-112
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    • 1995
  • Estimation of each of mean response, difference between mean responses and derivatives of the response function is a possible objective of a response surface design. These objectives are to be achieved simultaneously when an experiment is designed to improve mean response. For the situations where departure from the assumed model is suspected, first and second order designs for improving mean response are obtained by combining minimum bias designs for the individual design objectives. D- and A-optimalities are used for selecting specific second order designs. The results are applied to central composite designs.

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On a Modification of Warner's Randomized Response Model (Warner의 확률화 응답모형의 한 변형에 관하여)

  • Kim, Hyeok-Ju
    • Journal of Korean Society for Quality Management
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    • v.16 no.1
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    • pp.49-58
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    • 1988
  • When a question in a sample survey is sensitive or highly personal, respondents may prefer not to give truthful answers. To eliminate the resulting evasive answer bias Warner suggested a randomized response model. In this paper, a modification of Warner's method is presented and compared with Warner's method. The relation between this modified method and an unrelated question method is also discussed.

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Bias caused by nonresponses and suggestion for increasing response rate in the telephone survey on election (전화 선거여론조사에서 무응답률 증가로 인한 편의와 응답률 제고 방안)

  • Heo, Sunyeong;Yi, Sucheol
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.2
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    • pp.315-325
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    • 2016
  • Thanks to the advantages of low cost and quick results, public opinion polls on election in Korea have been generally conducted by telephone survey, even though it has critical disadvantage of low response rate. In public opinion polls on election in Korea, the general method to handle nonresponses is adjusting the survey weight to estimate parameters. This study first drives mathematical expression of estimator and its bias with variance estimators with/without nonresponses in election polls in Korea. We also investigates the nonresponse rate of telephone survey on 2012 Korea presidential election. The average response rate was barely about 14.4%. In addition, we conducted a survey in April 2014 on the respondents's attitude toward telephone surveys. In the survey, the first reason for which respondents do not answer on public opinion polls on election was "feel bothered". And the aged 20s group, the most low response group, also gave the same answer. We here suggest that survey researchers motivate survey respondents, specially younger group, to participate surveys and find methods boosting response rate such as giving incentive.

Optimal Designs for Multivariate Nonparametric Kernel Regression with Binary Data

  • Park, Dong-Ryeon
    • Communications for Statistical Applications and Methods
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    • v.2 no.2
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    • pp.243-248
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    • 1995
  • The problem of optimal design for a nonparametric regression with binary data is considered. The aim of the statistical analysis is the estimation of a quantal response surface in two dimensions. Bias, variance and IMSE of kernel estimates are derived. The optimal design density with respect to asymptotic IMSE is constructed.

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Attention Bias Toward Drug Cues in Female Methamphetamine Addicts (여성 메스암페타민 중독자의 약물 단서에 대한 주의편향)

  • Kim, Na-Yeon;Eum, Young-Ji;Kim, Kyo-Heon
    • Science of Emotion and Sensibility
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    • v.22 no.4
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    • pp.75-84
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    • 2019
  • Addicts pay more attention to addiction-related cues, such as substance or behavior. And increased attention to these cues is associated with craving. Methamphetamine is the most abused drug among domestic drug offenders, with continually increasing rates of recidivism. Of the total number of reported drug offenders in the last three years, 21.1 percent have been women. Even so, research on female drug offenders is inadequate, rendering policies and fundamental data for the development of psychotherapy programs insufficient. The present study intended to investigate whether female methamphetamine addicts displayed an attention bias towards drug cues. A dot probe task was conducted on 22 female methamphetamine addicts (addiction group) and 22 non-addicts (control group). The task allowed the correct response rates and correct reaction times of the participants to be calculated according to the positioning of the drug and neutral cues. The analysis results revealed that the control group displayed no difference in correct reaction rates and correct reaction times between the drug or neutral cues. While, the addiction group showed lower correct response rate and slower response time for drug cues in comparison to neutral cues. The results of this study are significant in that it identified the attention bias characteristics toward drug cues of female methamphetamine addicts who were disconnected from drugs.