Displaying publications 1 - 20 of 160 in total

  1. Arasan, Jayanthi
    This paper investigates several asymptotic confidence interval estimates, based on the Wald, likelihood ratio and the score statistics for the parameters of a parallel two-component system model, with dependent failure and a time varying covariate, when data is censored. This model is an extension of the bivariate exponential model. The procedures are investigated via a coverage probability study using the simulated data. The results clearly indicate that the interval estimates, based on the likelihood ratio method, work better than any of the other two methods when dealing with the censored data.
    Matched MeSH terms: Confidence Intervals
  2. Tan, Yih Tyng, Abdul Rahman Othman, Lai, Choo Heng
    Setting a question paper for test, quiz, and examination is one of the teachers’ tasks. The factors that are usually taken into consideration in carrying out this particular task are the level of difficulty of the questions and the level of the students’ ability. In addition, teachers will also have to consider the number of questions that have impact on the examination. This research describes a model-based test theory to study the confidence intervals for the projected number of items of a test, given the reliability of the test, the difficulty of the question, and the students’ ability. Using the simulated data, the confidence intervals of the projected number of items were examined. The probability coverage and the length of the confidence interval were also used to evaluate the confidence intervals. The results showed that the data with a normal distribution, the ratio variance components of 4:1:5 and reliability equal to 0.80 gave the best confidence interval for the projected number of items.
    Matched MeSH terms: Confidence Intervals
  3. Fauziah Maarof, Lim, Fong Peng, Noor Akma Ibrahim
    This paper investigates the confidence intervals of R2 MAD, the coefficient of determination based on
    median absolute deviation in the presence of outliers. Bootstrap bias-corrected accelerated (BCa)
    confidence intervals, known to have higher degree of correctness, are constructed for the mean and standard deviation of R2 MAD for samples generated from contaminated standard logistic distribution. The results indicate that by increasing the sample size and percentage of contaminants in the samples, and perturbing the location and scale of the distribution affect the lengths of the confidence intervals. The results obtained can also be used to verify the bound of R2 MAD.
    Matched MeSH terms: Confidence Intervals
  4. Kiani K, Arasan J, Habshah Midi
    Sains Malaysiana, 2012;41:471-480.
    There are numerous parametric models for analyzing survival data such as exponential, Weibull, log-normal and gamma. One of such models is the Gompertz model which is widely used in biology and demography. Most of these models are extended to new forms for accommodating different types of censoring mechanisms and different types of covariates. In this paper the performance of the Gompertz model with time-dependent covariate in the presence of right censored data was studied. Moreover, the performance of the model was compared at different censoring proportions (CP) and sample sizes. Also, the model was compared with fixed covariate model. In addition, the effect of fitting a fixed covariate model wrongly to a data with time-dependent covariate was studied. Finally, two confidence interval estimation techniques, Wald and jackknife, were applied to the parameters of this model and the performance of the methods was compared.
    Matched MeSH terms: Confidence Intervals
  5. Samira Ehsani, Jayanthi Arasan, Noor Akma Ibrahim
    Sains Malaysiana, 2013;42:981-987.
    In this paper, we extended a repairable system model under general repair that is based on repair history, to incorporate covariates. We calculated the bias, standard error and RMSE of the parameter estimates of this model at different sample sizes using simulated data. We applied the model to a real demonstration data and tested for existence of time trend, repair and covariate effects. Following that we also conducted a coverage probability study on the Wald confidence interval estimates. Finally we conducted hypothesis testing for the parameters of the model.The results indicated that the estimation procedure is working well for the proposed model but the Wald interval should be applied with much caution.
    Matched MeSH terms: Confidence Intervals
  6. Yii, Mei Wo, Zaharuddin Ahmad
    The studies of ¹³⁷Cs content in the seawater surrounding Peninsular Malaysia had been carried out as part of the Malaysia Marine Radioactivity Database Project. The results of the measurement will serve as the baseline data and reference level to Malaysia. A numbers of sampling locations, including coastal and offshore at the East Coast (South China Sea) and West Coast (Straits of Malacca) of Peninsular Malaysia had been selected for the study. From each location at the coastal area, water samples were collected from the surface of the seawater. Meanwhile, for the offshore area, water samples have been collected at three different depths. Due to usual low concentration of ¹³⁷Cs in the marine environment, large volumes of seawater were collected and the co precipitation technique was employed to concentrate the ¹³⁷Cs. The activity of ¹³⁷Cs was determined by measuring the peak area under photo peak of the gamma spectrum at 661 keV, which is equivalent to the gamma intensity corrected to the HpGe detection efficiency and percentage of gamma ray abundance of the ¹³⁴Cs. At each study location, there were no significant differences for ¹³⁷Cs activities at 95% confidence interval. The activities of ¹³⁷Cs found to be quite uniformly distributed in the range of 2.33 to 5.00 Bq/m3and 1.76 to 4.76 Bq/m3for the South China Sea and the Straits of Malacca, respectively.
    Matched MeSH terms: Confidence Intervals
  7. Nagandla K, Gupta ED, Motilal T, Teng CL, Gangadaran S
    Natl Med J India, 2019 7 4;31(5):293-295.
    PMID: 31267998 DOI: 10.4103/0970-258X.261197
    Background.: Assessment drives students' learning. It measures the level of students' understanding. We aimed to determine whether performance in continuous assessment can predict failure in the final professional examination results.

    Methods.: We retrieved the in-course continuous assessment (ICA) and final professional examination results of 3 cohorts of medical students (n = 245) from the examination unit of the International Medical University, Seremban, Malaysia. The ICA was 3 sets of composite marks derived from course works, which includes summative theory paper with short answer questions and 1 of the best answers. The clinical examination includes end-of-posting practical examination. These examinations are conducted every 6 months in semesters 6, 7 and 8; they are graded as pass/fail for each student. The final professional examination including modified essay questions (MEQs), 1 8-question objective structured practical examination (OSPE) and a 16-station objective structured clinical examination (OSCE), were graded as pass/fail. Failure in the continuous assessment that can predict failure in each component of the final professional examination was tested using chi-square test and presented as odds ratio (OR) with 95% confidence interval (CI).

    Results.: Failure in ICA in semesters 6-8 strongly predicts failure in MEQs, OSPE and OSCE of the final professional examination with OR of 3.8-14.3 (all analyses p< 0.001) and OR of 2.4-6.9 (p<0.05). However, the correlation was stronger with MEQs and OSPE compared to OSCE.

    Conclusion.: ICA with theory and clinical examination had a direct relationship with students' performance in the final examination and is a useful assessment tool.

    Matched MeSH terms: Confidence Intervals
  8. Titik, B., Naiyana, C.
    The objectives of this study were predicting the transmission and survival of L. monocytogenes in cooked ham during supply chain. Cooked ham are frequently contaminated with L. monocytogenes during postprocessing steps through contact on surface of processing, handling, packaging equipment. Transfer rate of L. monocytogenes on static and dynamic condition in various surface type was investigated. The prevalence and level of L. monocytogenes in cooked ham at plant as well as the prevalence of unsatisfactory processing at retail were studied. A Monte Carlo simulation model was created by using @risk. The simulation predicted that the prevalence was 11.76 % with 90% confidence interval of 2% to 25% and estimated level was -4.02 log CFU/cm2. It was estimated to be occurred on slicing step at plant. Our results suggest that, the prevalence and level of L. monocytogenes can be reduced by Good Handling Process application and/or HACCP application.
    Matched MeSH terms: Confidence Intervals
  9. Wan Nor Arifin, Wan Arfah Nadiah, Muhammad Irfan, Chen, Xin Wee, Nani Draman, Nyi, Nyi Naing
    To ensure the reliability of manual blood pressure (BP) readings in a clinical trial, sources of error due to measurement must be reduced as much as possible. Apart from following standard procedure for BP measurement and ensuring good equipments, the measurement errors that come from the assessors themselves should be assessed. Objective: To demonstrate the use of two-way random effects, interactions absent, absolute agreement (Type A), single measures (Type 1) intraclass correlation coefficient (ICC) in the assessment of reliability of manual BP readings among assessors involved in a clinical trial using manual BP measurement, by using an interrater reliability study conducted by the authors as an example study. Methods: The steps involved in obtaining ICC in the study were discussed. Sample size given the number of assessors in the study was calculated. BP was measured using regularly maintained mercury sphygnomanometers, following recommendations by Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) for BP measurement in office setting. The outcomes were systolic and diastolic BP readings. A type of ICC, two-way random effects, interactions absent, absolute agreement (Type A), single measures (Type 1) ICC was chosen for the analysis and specifically discussed. Pre-requisite assumptions for ICC were meticulously checked and described. The interrater reliability for systolic and diastolic BP readings as expressed by ICC (single measure) were presented with confidence interval (CI). The ICCs obtained in the example study were discussed and concluded. The flaws of the study were also criticised. Results: The interrater reliability for systolic and diastolic BP measurements as expressed by ICC (single measure) were 0.87 (95% confidence interval [CI] 0.722, 0.956) and 0.77 (95% CI 0.560, 0.918) respectively. Conclusion: We demonstrated the steps required to obtain ICC. Since the use of manual BP measurement using mercury sphygmomanometer is still considered as gold standard of BP measurement, it is important that studies in which the BP outcome is measured using such method conduct interrater reliability studies properly.
    Matched MeSH terms: Confidence Intervals
  10. Iliassa II, Mohammad WM, Tan JJ, Ayob Y
    Asian J Transfus Sci, 2016 Jul-Dec;10(2):145-9.
    PMID: 27605853 DOI: 10.4103/0973-6247.187934
    BACKGROUND: Cryoprecipitate is generally used to treat bleeding patients with hypofibrinogenemia, and the transfusion decision is guided based on published guidelines.
    AIM: This study aimed to evaluate the practice appropriateness in accordance to cryoprecipitate transfusion guidelines in Hospital Kuala Lumpur.
    METHODOLOGY: This cross-sectional study of 117 cryoprecipitates transfused adult patients was conducted in Kuala Lumpur Hospital from January to June 2012. The compliance of the indication of cryoprecipitate was considered as appropriate if indicated for patients who have hypofibrinogenemia (<1.0 g/L) with bleeding, or otherwise inappropriate if pretransfusion fibrinogen level was more than 1.0 g/L, pretransfusion fibrinogen level was not examined and posttransfusion fibrinogen level more than 1.5 g/L.
    RESULTS: Most of the cryoprecipitate prescriptions were found to be inappropriate, which read 81.2% (95% confidence interval = 0.740, 0.880). Patients who underwent neurovascular surgery were the major recipient of cryoprecipitate, but majority of the prescription was found not appropriate. The decision to transfuse cryoprecipitate was found mostly appropriate when was guided by fibrinogen (52.2%), but the percentage dropped to 10.6% when pretransfusion fibrinogen test was not performed. Regrettably, only 19.7% of total cryoprecipitate were given based on pretransfusion fibrinogen level.
    KEYWORDS: Appropriateness; bleeding; cryoprecipitate transfusion; guideline
    Matched MeSH terms: Confidence Intervals
  11. Yong, W.Z., Haresh, K.K., Wong, W.C., 1 Pui, C.F., Son, R.
    The objectives highlighted in the present study were to determine the estimates of measurement uncertainty associated with PALCAM and CHROMagarTM Listeria media, to compare the efficacy between both media in relation to their measurement uncertainties. In addition, this study was carried out to assess the performance characteristics of spread and spiral plating procedures based on the comparison of Listeria monocytogenes enumeration between PALCAM and CHROMagarTM Listeria media. This work involved pure culture experiment, artificially contaminated samples experiment and naturally contaminated samples experiment. In pure culture experiment, PALCAM performance was relatively inferior to CHROMagarTM Listeria medium for both plating procedures. From the artificially contaminated samples, the results revealed that the values of repeatability, reproducibility, and measurement uncertainty at 95% confidence interval were comparable between both media under evaluation. However, at the level of naturally contaminated samples, the performance of CHROMagar
    TM Listeria medium was refutable as the presence of high number of competitive microorganisms reduced the clarity of the medium. The current emphasis in ensuring microbiological safety which requires use of accredited laboratories has led to measurable need for measurement uncertainty to ensure reliability of test results for global acceptance.
    Matched MeSH terms: Confidence Intervals
  12. New, C.Y., Ubong, A., Nur Hasria, K., Nur Fatihah, A., Son, R.
    Vibrio parahaemolyticus is well known to be abundantly distributed in marine, coastal and
    estuarine environments. Since 1951, V. parahaemolyticus had been the source of numerous
    outbreaks related to contaminated or mishandled seafood. However, V. parahaemolyticus
    had been detected on other types of food. This issue has prompted this study to investigate
    on the prevalence of V. parahaemolyticus in various food samples and determine the risk
    associated with it. The results of the MPN-plating technique of the study indicated that V.
    parahaemolyticus was detected in seafood (33.3%, 95% Confidence Interval [CI] 31.9 – 34.8 ,
    94 – 290 MPN/g) and vegetables (10.0%, 95% CI 9.7 – 10.3 , 9.2 – 23 MPN/g) while negative
    V. parahaemolyticus was detected in fruits (0.0%, 95% CI 0 – 1,
    Matched MeSH terms: Confidence Intervals
  13. Rajah R, Hassali MAA, Murugiah MK
    Public Health, 2019 Feb;167:8-15.
    PMID: 30544041 DOI: 10.1016/j.puhe.2018.09.028
    OBJECTIVES: Health literacy is increasingly recognized as a public health concern. Most of the literature on health literacy concentrate in the Western countries. Therefore, this study aimed to systematically review and examine the available studies on health literacy in Southeast Asian countries and estimate its prevalence in this region.

    STUDY DESIGN: Systematic review.

    METHODS: A search for relevant articles was carried out using Cumulative Index to Nursing and Allied Health Literature (CINAHL) and MEDLINE (via EBSCOhost), Scopus, Science Direct, PubMed and Google Scholar with multiple search terms. Inclusion criteria comprised articles published in English language and assessing general health literacy. Risk of bias reduced with the involvement of two independent reviewers in the screening of the literature and the quality assessment process.

    RESULTS: A total of 11 studies were included, which only consist of studies from five countries out of 11 making up the Southeast Asian region. The overall prevalence of limited health literacy varied considerably, 1.6%-99.5% with a mean of 55.3% (95% confidence interval [CI]: 35.1%-75.6%). A much higher prevalence was noted in studies conducted in healthcare settings, 67.5% (95% CI: 48.6%-86.3%). The most common factors associated with limited health literacy were education attainment, age, income and socio-economic background. Other factors identified were gender and health behaviours.

    CONCLUSIONS: In summary, despite the little evidence available and existences of high heterogeneity among studies, limited health literacy is still prevalent in Southeast Asian countries. Urgent strategies to improve and promote health literacy in the region are highly warranted. Besides, more studies on health literacy with better quality on the methodology aspect are needed.

    Matched MeSH terms: Confidence Intervals
  14. Lall P, Saifi R, Baggio D, Schoenberger SF, Choo M, Gilbert L, et al.
    Asia Pac J Public Health, 2019 Apr;31(3):227-237.
    PMID: 30983376 DOI: 10.1177/1010539519841294
    Malaysia currently has an estimated hepatitis C virus (HCV) prevalence of 1.3% with an infected population of 384,000. Fishermen in Malaysia are at risk of HCV infection due to injection drug use and disproportionately high rates of incarceration. This study used quantitative data from Project WAVES, a large-scale mixed methods project charting environmental drivers of risk-taking behaviors among a respondent-driven sample of 406 fishermen in Malaysia. Over a quarter of participants (27.9%) reported injecting drugs in the past month; 49.8% of the sample tested positive for HCV. Respondents who had previously been arrested displayed increased odds of being HCV-positive (adjusted odds ratio = 4.79, confidence Interval = 2.46-9.35). Participants who reported being in lock-up displayed close to 6-fold odds of being HCV-infected (adjusted odds ratio = 5.49, confidence interval = 2.77-10.90, P < .001). These findings underscore the need for policies and structural interventions targeting the negative effects of aggressive incarceration contributing to the burden of HCV among high-risk communities.
    Matched MeSH terms: Confidence Intervals
  15. Ab Rahman J, Mohd Yusoff MF, Nik Mohamed MH, Mahadir Naidu B, Hock LK, Hiong TG, et al.
    PMID: 30880403 DOI: 10.1177/1010539519834735
    Electronic cigarettes (e-cigarettes) are a new method for the consumption of nicotine. A nationwide survey among 4288 Malaysian adults was conducted in 2016 to measure the prevalence and to describe the population characteristics of e-cigarette users. A complex sampling design was used, and data were collected using a face-to-face questionnaire. The overall prevalence of current, ever, former, and dual users of e-cigarettes in Malaysia were 3.2% (95% confidence interval [CI] = 2.5-4.1), 11.9% (95% CI = 10.5-13.5), 8.6% (95% CI = 7.5-9.8), and 2.3% (95% CI = 1.8-3.1), respectively. The prevalence of all type of e-cigarette use was higher in urban than in rural areas. Current e-cigarette users were likely to be younger, males, and with higher education level. Among current e-cigarette users, 74% (95% CI = 64-82) also smoked conventional cigarettes (dual user). E-cigarette use is prevalent in Malaysia. It is common among younger adults, males, and cigarette smokers.
    Matched MeSH terms: Confidence Intervals
  16. Wu Y, Levis B, Riehm KE, Saadat N, Levis AW, Azar M, et al.
    Psychol Med, 2019 Jul 12.
    PMID: 31298180 DOI: 10.1017/S0033291719001314
    BACKGROUND: Item 9 of the Patient Health Questionnaire-9 (PHQ-9) queries about thoughts of death and self-harm, but not suicidality. Although it is sometimes used to assess suicide risk, most positive responses are not associated with suicidality. The PHQ-8, which omits Item 9, is thus increasingly used in research. We assessed equivalency of total score correlations and the diagnostic accuracy to detect major depression of the PHQ-8 and PHQ-9.

    METHODS: We conducted an individual patient data meta-analysis. We fit bivariate random-effects models to assess diagnostic accuracy.

    RESULTS: 16 742 participants (2097 major depression cases) from 54 studies were included. The correlation between PHQ-8 and PHQ-9 scores was 0.996 (95% confidence interval 0.996 to 0.996). The standard cutoff score of 10 for the PHQ-9 maximized sensitivity + specificity for the PHQ-8 among studies that used a semi-structured diagnostic interview reference standard (N = 27). At cutoff 10, the PHQ-8 was less sensitive by 0.02 (-0.06 to 0.00) and more specific by 0.01 (0.00 to 0.01) among those studies (N = 27), with similar results for studies that used other types of interviews (N = 27). For all 54 primary studies combined, across all cutoffs, the PHQ-8 was less sensitive than the PHQ-9 by 0.00 to 0.05 (0.03 at cutoff 10), and specificity was within 0.01 for all cutoffs (0.00 to 0.01).

    CONCLUSIONS: PHQ-8 and PHQ-9 total scores were similar. Sensitivity may be minimally reduced with the PHQ-8, but specificity is similar.

    Matched MeSH terms: Confidence Intervals
  17. Ros Syazmini Mohd Ghani, Razak Wahab, Noor Maisarah Che Musthafa, Nasihah Mokhtar, Mohamad Saiful Sulaiman, Lee, Man Djun
    The study was carried out to determine the physical and mechanical properties of composite lumber made from cassava (Mahinot esculenta Crantz) and bamboo (Bambusa vulgaris) in different ratios which is 100% cassava with 0% bamboo, 75% cassava with 25% bamboo, 50% cassava with 50% bamboo, 25% cassava with 75% bamboo and 0% cassava with 100% bamboo. The tests samples for determining the strength properties were divided into two categories namely mechanical testing and physical testing. Basic density of the samples was carried out for physical testing. The lowest basic density was in samples with 100% cassava which is 0.49 g/cm3 and highest in samples with 100% bamboo which is 0.68 g/cm3. Two tests for the mechanical testing are bending test and compression test. In bending test, modulus of elasticity (MOE) and modulus of rupture (MOR) were both highest for samples with 100% bamboo which the reading of MOE was 16794.03 N/mm2 and 122.52 N/mm2 for MOR. Similar to the bending test, compression test is the highest for the samples with 100% bamboo which are 65.58 N/mm2. From statistical analysis, the basic density, static bending can compression strength give significant value at 95% confidence interval.
    Matched MeSH terms: Confidence Intervals
  18. Dzulkarnain AAA, Sani MKA, Rahmat S, Jusoh M
    J Audiol Otol, 2019 Jul;23(3):121-128.
    PMID: 30857383 DOI: 10.7874/jao.2018.00381
    BACKGROUND AND OBJECTIVES: There is a scant evidence on the use of simulations in audiology (especially in Malaysia) for case-history taking, although this technique is widely used for training medical and nursing students. Feedback is one of the important components in simulations training; however, it is unknown if feedback by instructors could influence the simulated patient (SP) training outcome for case-history taking among audiology students. Aim of the present study is to determine whether the SP training with feedback in addition to the standard role-play and seminar training is an effective learning tool for audiology case-history taking.

    SUBJECTS AND METHODS: Twenty-six second-year undergraduate audiology students participated. A cross-over study design was used. All students initially attended two hours of seminar and role-play sessions. They were then divided into three types of training, 1) SP training (Group A), 2) SP with feedback (Group B), and 3) a non-additional training group (Group C). After two training sessions, the students changed their types of training to, 1) Group A and C: SP training with feedback, and 2) Group B: non-additional training. All the groups were assessed at three points: 1) pre-test, 2) intermediate, and 3) post-test. The normalized median score differences between and within the respective groups were analysed using non-parametric tests at 95% confidence intervals.

    RESULTS: Groups with additional SP trainings (with and without feedback) showed a significantly higher normalized gain score than no training group (p<0.05).

    CONCLUSIONS: The SP training (with/ without feedback) is a beneficial learning tool for history taking to students in audiology major.

    Matched MeSH terms: Confidence Intervals
  19. Naing C, Aung K, Mak JW
    J Evid Based Med, 2012 Nov;5(4):232-7.
    PMID: 23557504 DOI: 10.1111/jebm.12002
    In translating clinical research into practice, the summarization of data from randomized trials in terms of measures of effect to be readily appreciated by the point-of-care clinicians is important. In this context, the body of literature highlighted the 'number needed to treat' as a useful measure. The objectives of our study were to assess how meta-analyses described number needed to treat and corresponding 95% CI, and to explore issues related to reporting number needed to treat in the selected meta-analyses.
    Matched MeSH terms: Confidence Intervals
  20. Lee MY, Teh NC, Nur Zulekha M, Thayanithi S, Jelinar MN, Rizal AM, et al.
    Asia Pac J Ophthalmol (Phila), 2012 Jul-Aug;1(4):208-12.
    PMID: 26107474 DOI: 10.1097/APO.0b013e31825c5b1b
    To compare the effects of fixed combination of bimatoprost-timolol and travoprost-timolol on intraocular pressure (IOP) in patients with primary open-angle glaucoma or ocular hypertension.
    This was a prospective, randomized, observer-masked, crossover parallel comparison trial.
    Forty-one patients with primary open-angle glaucoma or ocular hypertension on nonfixed combination of latanoprost and timolol with IOP of 21 mm Hg or less were randomized to either bimatoprost-timolol or travoprost-timolol fixed combinations for 8-week treatment period. Intraocular pressure was measured at 8 AM, 12 PM, 4 PM, and 8 PM at the baseline and at the end point. Conjunctiva hyperemia and superficial punctate keratopathy after treatment with each fixed combination therapy were assessed and compared with the baseline. Patients were then switched to the opposite drug without a medication-free period for another 8-week, and diurnal IOP measurement was repeated.
    Bimatoprost-timolol fixed combination reduced the baseline mean diurnal IOP statistically significantly from 17.3 mm Hg [95% confidence interval (CI), 16.8-17.7 mm Hg] to 16.4 mm Hg (95% CI, 15.9-17.0 mm Hg) (P = 0.036). Travoprost-timolol fixed combination lowered the mean diurnal IOP to 17.1 mm Hg (95% CI, 16.5-17.7 mm Hg), but it was not significant. Direct comparison between the 2 fixed combinations showed no significant difference. Both fixed combinations had no significant effect on conjunctiva hyperemia. Interestingly, patients on travoprost-timolol fixed combination had significantly less superficial punctuate keratopathy (P = 0.012).
    Both fixed combination of bimatoprost-timolol and travoprost-timolol had no significantly different ocular hypotensive effect. However, bimatoprost-timolol fixed combination produced additional IOP lowering in patients previously treated with nonfixed combination of latanoprost and timolol.
    Matched MeSH terms: Confidence Intervals
Contact Us

Please provide feedback to Administrator (tengcl@gmail.com)

External Links