Estimating the Population Standard Deviation with Confidence Interval: A Simulation Study under Skewed and Symmetric Conditions

This paper investigates the performance of ten methods for constructing a confidence interval estimator for the population standard deviation by a simulation study. Since a theoretical comparison among the interval estimators is not possible, a simulation study has been conducted to compare the performance of the selected interval estimators. Data were randomly generated from several distributions with a range of sample sizes. Various evaluation criterions are considered for performance comparison. Two health related data have been analyzed to illustrate the application of the proposed confidence intervals. Based on simulation results, some intervals with the best performance have been recommended for practitioners

A Comparison of Some Robust Bicariate Control Charts for Individual Observations

This paper proposed and considered some bivariate control charts to monitor individual observations from a statistical process control. Usual control charts which use mean and variance-covariance estimators are sensitive to outliers. We consider the following robust alternatives to the classical Hoteling’s T2: T2MedMAD, T2MCD, T2MVE A simulation study has been conducted to compare the performance of these control charts. Two real life data are analyzed to illustrate the application of these robust alternatives

Effects of metronidazole and probiotics oligosaccharide on bacterial translocation in protein malnutrition

The present study aims to evaluate the effects of metronidazole, probiotics oligosaccharide on indigenous microflora and bacterial translocation (BT) in protein malnourished rats. Thirty male Wistarrats were divided into three groups: protein malnourished rats PM (group1, n = 10) were fed with maize only, protein malnourished rats (group 2, n = 10) were received metronidazole and protein malnourished rats (group 3, n = 10) were received both metronidazole and probiotics-oligosaccharide for fifteen days. Metronidazole (1000 mg/kg/day) was given via an orogastric feeding tube to the second and third groups. Lyophilized probiotics-oligosaccharide (0.5 mg/g body weight/day) was given in two doses via the same route to the third group. All animals were sacrificed after fifteen days of protein malnutrition and cultures of the mesenteric lymph nodes (MLNs), liver, spleen and cecal contents were done. Theincidence of bacterial translocation (BT) was 30% (3/10) in protein malnourished group 1,60% (06/10) in group 2 where protein malnutrition was associated with metronidazole and 25% (2.5/10) in group 3whose animals were subjected to protein malnutrition associated with metronidazole and probiotics oligosaccharide. A significant increase in the BT incidence was found in group 2 (P < 0.05), while a significant decrease was found in group 3 when compared to group 1. The total bacterial count of cecal flora was significantly low in group 3 than in group 1 (P < 0.01). These results suggest that the incidence of BT in protein malnutrition is increased by using an antibiotic while probioticsoligosaccharide decreases this incidence in protein malnutrition induced by antibiotic. Thus, weconclude that probiotics-oligosaccharide can effectively protect the intestinal mucosa and prevent BT in protein malnourished infants

Voluntary activation failure is detectable in some myositis patients with persisting quadriceps femoris weakness: an observational study

This cross-sectional, observational study was undertaken to examine whether voluntary activation failure could contribute to the persisting weakness observed in some patients with treated idiopathic inflammatory myositis. In 20 patients with myositis of more than six months' duration (5 males, 15 females; mean [± 1 SD] age 53 [11] years) and 102 normal subjects (44 males, 58 females; mean age 32 [8] years), isometric maximum voluntary contractions (MVCs) of the dominant quadriceps femoris (QF) were quantified. Absolute MVC results of normal subjects and patients were then normalised with respect to lean body mass (force per units of lean body mass), giving a result in Newtons per kilogram. Based on mass-normalised force data of normal subjects, patients were arbitrarily stratified into "weak" and "not weak" subgroups. During further MVC attempts, the "twitch interpolation" technique was used to assess whether the QF voluntary activation of patients was complete. This technique relies on the fact that, because muscle activation is incomplete during submaximal voluntary contractions, electrical stimulation of the muscle can induce force increments superimposed on the submaximal voluntary force being generated. No between-gender differences were seen in the mass-normalised MVC results of healthy subjects, so the gender-combined results of 6.6 (1.5) N/kg were used for patient stratification. No between-gender difference was found for mass-normalised MVCs in patients: males 5.4 (3.2) and females 3.0 (1.7) N/kg (p > 0.05). Mass-normalised MVCs of male patients were as great as those of normal subjects (p > 0.05), but mass-normalised MVCs of female patients were significantly smaller than those of the normal subjects (p < 0.001). Only one of the six "not weak" patients exhibited interpolated twitches during electrical stimulation, but six of the 14 "weak" patients did, the biggest twitches being seen in the weakest patient. That interpolated twitches can be induced in some myositis patients with ongoing QF weakness during supposed MVCs clearly suggests that voluntary activation failure does contribute to QF weakness in those patients

Tax Literacy Rate Among Taxpayers: Evidence From Malaysia

The extent of taxpayer knowledge can have a major impact on the degree of compliance with taxation rules and regulation. Low knowledge creates uncertainty about requirements of the tax regulation and can lead to high degree of involun-tary non-compliance. This study high¬lighted the importance of taxation knowledge by measuring Malaysian’s tax payers’ tax literacy rate taking into consideration the following criteria: 1) Individual ability to fill the tax return form inde¬pendently, 2) Taxpayer’s interest in learning about tax, and 3) Incident of errors in filling the tax re¬turn forms. Questionnaires were used in this study to ascertain the tax liter-acy rate. The results in¬dicate that among the respondents, professionals group has the highest percentage of tax literacy and the formers have the lowest percentage. Majority of the businessmen paid for services for fill¬ing tax return forms and high rank officers are the highest among the group for not employing oth¬ers for filling the tax forms. Businessmen have the highest incidence of error in filling tax return form and most of teachers reported no error in filling such forms. Most business-men showed interests and were willing to spend time to learn about taxation. They perceived taxation knowledge as an important tool for themselves and also for their family. Overall results indicate that more than 60% of respondents are tax lit-erate. However, a significant number of them are actually‘ functionally tax illiter-ate’. Most of them thought that they knew a lot about taxation as they had read them in the tax literature sent to them by the IRB. However, the evidence was con-trary to this conjecture. The in¬formation on the extent of taxpayers’ knowledge is potentially useful to the tax authorities to assist them in developing effective com-pliance enhancement policie

First-order intertwining operators with position dependent mass and η\eta- weak-psuedo-Hermiticity generators

A Hermitian and an anti-Hermitian first-order intertwining operators are introduced and a class of $\eta$-weak-pseudo-Hermitian position-dependent mass (PDM) Hamiltonians are constructed. A corresponding reference-target $\eta$-weak-pseudo-Hermitian PDM -- Hamiltonians' map is suggested. Some $\eta$-weak-pseudo-Hermitian PT -symmetric Scarf II and periodic-type models are used as illustrative examples. Energy-levels crossing and flown-away states phenomena are reported for the resulting Scarf II spectrum. Some of the corresponding $\eta$-weak-pseudo-Hermitian Scarf II- and periodic-type-isospectral models (PT -symmetric and non-PT -symmetric) are given as products of the reference-target map.Comment: 11 pages, no figures, Revised/Expanded, more references added. To appear in the Int.J. Theor. Phy

A simulation study on some confidence intervals for the population standard deviation

In this paper a robust estimator against outliers along with some other existing interval estimators are considered for estimating the population standard deviation. An extensive simulation study has been conducted to compare and evaluate the performance of the interval estimators. The exact and the proposed robust method are easy to calculate and are not overly computer-intensive. It appears that the proposed robust method is performing better than other confidence intervals for estimating the population standard deviation, specifically in the presence of outliers and/or data are from a skewed distribution. Some real-life examples are considered to illustrate the application of the proposed confidence intervals, which also supported the simulation study to some extent