Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Binomial Distribution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
PubMed1999

Estimations of the efficacy and reliability of paternity assignments from DNA microsatellite analysis of multiple-sire matings.

It is important for bovine DNA testing laboratories to provide the cattle industry with accurate estimates of the efficacy and reliability of DNA tests offered so that end users of this technology can adequately assess the cost-benefits of testing. To address these issues for bovine paternity testing, paternity exclusion probability estimates were obtained from breed panel data and were predictive of the efficacy of the DNA tests used in 39 multiple-sire mating groups, involving 5960 calves and 505 bulls. Paternity testing of these mating groups has demonstrated that the majority involve a variable proportion of unknown sires and this impacts on the reliability of sire allocation. Mathematical models based on binomial or beta-binomial probability distributions were used to estimate the reliability of single-sire allocations from multiple-sire matings involving unknown sires. Reliability of 98-99% is achieved when the exclusion probability is 0.99 or greater, after allowing for up to 20% unknown sires. When the exclusion probability drops below 0.90 and there are 20% unknown sires, the reliability is poor, bringing into question the benefits of testing. This highlights the need for DNA testing laboratories to offer paternity tests with an exclusion power of at least 99%.

Animals↗
PubMed2001

Has the perception of disability among COPD patients applying for pension changed during the last 20 years?

The aim is to examine the change in lung function, treatment and pulmonary symptoms in patients with chronic obstructive pulmonary disease (COPD) or chronic bronchitis (CB) applying for a pension during the period 1977-1996. In addition, we compared the perception of disability in males and females. From 1977 to 1996, 947 patients with COPD or CB were evaluated for obtaining economic support due to disability. In order to test the trend, the patients were divided into three periods: (1) 1977-1983, (2) 1984-1989 and (3) 1990-1996. Compared to females, males had substantial more pack-years of smoking (36 vs. 28, P<0.001), but their FEV1 was only slightly decreased (46.9% versus 49.6% predicted, P=0.047). Females reported significantly more often attacks of dyspnoea [OR: 1.5(1.00-2.2)] and any kind of dyspnoea during daytime [OR: 4.0(1.2-13.3)]. From period 1 to period 3, FEV1 increased significantly (45-53% predicted, P<0.001). Despite the increased FEV1, the use of inhaled corticosteroid had increased markedly (9-32% of the patients, P<0.001). The results did not change when patients with asthma were included. Our data suggest that both sexes, especially females, have become more aware of pulmonary symptoms and tend to react to them more actively by demanding evaluation and treatment.

Asthma↗
PubMed2003

[Evaluation of continuing medical education (CME) in print media].

BACKGROUND AND OBJECTIVE: In order to achieve points for the CME certificate of the German Medical Council ("Arztekammer") the reader of a CME article in a medical journal has to fill in an evaluation form that includes knowledge assessment. This article summarizes the data of the first ten CME presentations in the "Deutsche Medizinische Wochenschrift". METHODS: 4481 completed data sets were evaluated by chi-square and binomial tests using SPSS version 10.0. RESULTS: 85% of the participants were specialists, mainly in internal medicine or surgery: those working in private practice or a hospital took part. The great majority had received their licence one to 30 years ago. The topics dealt with diseases which were not uniformly often seen in clinical practice. The individually perceived changes in the strategy of diagnosis and therapy, induced by the CME article, was mainly dependent on qualification and specialization of the reader as well as on the frequency, with which the reader had been treating the respective disorder. The articles were appreciated by specialists as well as by non-specialists. Knowledge assessment was largely made on the basis of the article alone and was successfully passed by nearly 90% of the participants. CONCLUSION: For the first time this article provides detailed data on CME activities in a nation-wide available German medical journal and thus forms the basis for discussing further the definition of quality criteria for CME articles in medical journals.

Binomial Distribution↗
PubMed2003

Variations among emergency departments in the treatment of benign headache.

STUDY OBJECTIVE: The practice patterns of US emergency departments in the treatment of patients with isolated benign headache have been recently described. How treatment varies among EDs has not been reported. To assess institutional variability in the pharmacotherapy of patients with benign headache, we describe and analyze the practice patterns of 3 US EDs. METHODS: This health records survey included a cohort sample of consecutive adult patients aged 16 to 65 years treated with parenteral medication for isolated benign headache at 3 nonaffiliated US EDs: a large, group-model health maintenance organization, a tertiary-care academic center, and a rural community hospital. Patients who underwent a diagnostic search for intracranial pathology, who had any nonheadache secondary diagnosis, or who had coexistent trauma, fever (temperature of > or =38.0 degrees C [100.4 degrees F]), or known pregnancy were excluded from study analysis. Demographic, clinical, and pharmacotherapeutic variables were collected for each ED visit. Descriptive analyses were performed; comparisons were made with t tests. RESULTS: Of the 490 eligible patients treated during the 4-month study period, the mean age was 36.4 years, and 374 (76%) were women. During their 629 visits, 364 (58%) received a migraine diagnosis, and 258 (41%) received a nonspecific headache diagnosis. Polypharmacy was common: 515 (82%) received 2 or more medications, and 154 (25%) received 3 or more medications. Pharmacotherapy varied greatly among the EDs. Use of opioid agonists showed the widest variation (16% to 72%), although use of dihydroergotamine (5% to 16%), prochlorperazine (32% to 59%), and adjunct diphenhydramine with prochlorperazine (42% versus 88%) also varied. CONCLUSION: Great institutional variability exists among US EDs in the parenteral treatment of patients with isolated benign headache.

Adolescent↗
PubMed2001

Noninvasive assessment of left ventricular isovolumic contraction and relaxation with continuous wave Doppler aortic regurgitant velocity signals: an in vivo validation study.

The purpose of this study was to provide fundamental in vivo validation of a method with the use of aortic regurgitant (AR) jet signals recorded with continuous wave (CW) Doppler for assessing left ventricular (LV) isovolumic contraction and relaxation. Preliminary studies have suggested that analysis of CW Doppler AR velocity signals permits the estimation of LV positive and negative dP/dt. We studied 19 hemodynamically different states in 6 sheep with surgically induced chronic aortic regurgitation. CW AR velocity spectra and high-fidelity LV and aortic pressures were recorded simultaneously. Rates of LV pressure rise and fall (RPR and RPF) were calculated by determining the time interval between points at 1 m/s and 2.5 m/s in the deceleration and acceleration slopes of the CW Doppler AR velocity envelope (corresponding to a pressure change of 21 mm Hg). RPR and RPF calculated by CW Doppler analysis for each state were compared with the peak positive dP/dt and negative dP/dt, obtained from the corresponding high-fidelity LV pressure curve, respectively. The LV peak positive and negative dP/dt derived by catheter ranged from 817 to 2625 mm Hg/s and from 917 to 2583 mm Hg/s, respectively. Multiple regression analysis showed that Doppler RPR correlated well with catheter peak positive dP/dt (r = 0.93; mean differences, -413 +/- 250 mm Hg/s). There was also good correlation and agreement between Doppler RPF and the catheter peak negative dP/dt (r = 0.89; mean difference, -279 +/- 239 mm Hg/s). Both Doppler-determined RPR and RPF underestimated their respective LV peak dP/dt. CW Doppler AR spectra can provide a reliable noninvasive estimate of LV dP/dt and could be helpful in the serial assessment of ventricular function in patients with aortic regurgitation.

Animals↗
PubMed2000

Direct oral microscopy and its value in diagnosing mucosal lesions: a pilot study.

OBJECTIVE: Clinical examination of the oral mucosa often leads to an uncertain diagnosis, and a supplementary biopsy with a histopathologic examination of the lesion is necessary to establish a definite diagnosis. However, the site for the biopsy is a subjective choice that sometimes raises doubts about its representativeness. So far, no simple and reliable method is available for selecting the most appropriate area for biopsy. STUDY DESIGN: In a prospective study, we performed direct oral microscopy (oral application of the colposcopy technique used in gynecology) in 35 patients with various clinical diagnoses, such as leukoplakia, oral lichenoid lesions, or suspected malignancy. First, the oral mucosa was examined with direct microscopy, and the most representative site, according to colposcopic criteria, was selected. Then, the mucosa was clinically inspected by an independent examiner. The best site for biopsy according to clinical criteria was noted, and any difference in biopsy sites was recorded. Biopsy specimens were taken from 2 of these sites. RESULTS: Twenty-nine patients (83%) showed changes in the vascular picture on microscopy, according to the colposcopy criteria. In 14 patients (40%), the biopsy sites identified by direct oral microscopy showed more advanced histologic signs than those selected by routine clinical examination (0.01 < P </=.05). Four patients (11%) had more advanced histologic signs in the biopsy samples, as identified during routine clinical examination. In 17 patients (49%), we found no differences between the biopsy specimens. CONCLUSION: Direct oral microscopy of mucosal lesions seems to offer advantages in selecting more representative sites for biopsy than routine clinical examination alone.

Adult↗
PubMed2001

Bacteria isolated after unsuccessful endodontic treatment in a North American population.

OBJECTIVE: The purpose of this study was to determine the composition of the microbial flora present in teeth after the failure of root canal therapy in a North American population. These results were then compared with those of the previous Scandinavian studies. STUDY DESIGN: Fifty-four root-filled teeth with persistent periapical radiolucencies were selected for retreatment. After removal of the root-filling material, the canals were sampled with paper points, and by reaming of the apical dentin. Both samples were grown under aerobic and strict anaerobic conditions. Then the bacterial growth was analyzed. RESULTS: The microbial flora was mainly of 1 to 2 strains of predominantly gram-positive organisms. Enterococcus faecalis was the most commonly recovered bacterial species. CONCLUSIONS: Bacteria were cultivated in 34 of the 54 teeth examined in the study. E faecalis was identified in 30% of the teeth with a positive culture.

Actinomyces↗
PubMed2001

Thirst modulates a perception.

Does thirst make you more likely to think you see water? Tales of thirsty desert travelers and oasis mirages are consistent with our intuitions that appetitive state can influence what we see in the world. Yet there has been surprisingly little scrutiny of this appetitive modulation of perception. We tested whether dehydrated subjects would be biased towards perceptions of transparency, a common property of water. We found that thirsty subjects have a greater tendency to perceive transparency in ambiguous stimuli, revealing an ecologically appropriate modulation of the visual system by a basic appetitive motive.

Binomial Distribution↗
PubMedDate not supplied

Genetic and environmental sources on familial transmission in Basque families. II. Stature, weight and body mass index.

PRIMARY OBJECTIVE: The present research analyses a cross-sectional sample of 359 individuals (107 fathers, 107 mothers, 71 sons and 74 daughters) in 107 nuclear families from the Basque Country (Spain). The aim was the estimation of both transmissible and non-transmissible components acting on familial resemblance for stature, weight and body mass index (BMI). METHODS: Standardized data of each generation and sex were adjusted to a BETA model of path analysis independent of sex effects, allowing the possibility of differentiating between transmissible (genetic and cultural) and non-transmissible (environmental) components acting on the observed phenotypic variance in Biscayan offspring. RESULTS: The results supported the full model of familial transmission for the three variables, in addition to other reduced models that gave rise to transmission effects regardless of any influence from the siblings' shared environment on the environmental transmitted component from their parents (b = 0), and without genetic effects on the phenotype (h = z = 0). The most parsimonious model was accepted for weight and rejected for stature and BMI. The correlations existing between children and their mothers were higher than those with their fathers. CONCLUSION: The results confirmed the hypothesis of maternal effects influencing the inheritance of stature.

Adolescent↗
PubMed1996

TMD diagnostic decision-making and probability theory. Part I.

This article is an educational analysis and discussion of some recently proposed diagnostic criteria, diagnostic methods, and diagnostic decision processes, pertaining specifically to temporomandibular disorders (TMD). On the basis of a discussion of classic probability theory, classic measurement theory, and examples using nonparametric inferential statistical tests, it is suggested that certain TMD diagnostic criteria and methods, and their associated decision matrix, favor subjective clinical opinions (largely pseudoscientific observations) and arbitrary clinical indices rather than objective scientific facts.

Binomial Distribution↗
PubMed1998

Determination of allele frequency from DNA pools using bovine trinucleotide microsatellites.

Three sets of fluorescent labelled primers were used to amplify bovine trinucleotide microsatellites from DNA pools. DNA from 20 individuals were collected to create 3 pools differing in allele frequencies. Replicate mixes from each pool were used as template for PCR reactions. PCR products were separated and quantified on an automated DNA sequencer. Allele frequency estimates from pooled samples corrected for overlapping shadow peaks were calculated. Rare alleles representing only 2.5% of the total pool were accurately detected. Standard error of allele frequency estimates expressed as percent of the total 40 chromosomes per pool ranged between 0.8%-4.6% for different microsatellite-pool combinations as compared to 8.0% binomial sampling error. Regression coefficients of actual allele frequencies, determined by individual genotyping, on estimated frequencies ranged from 0.96-1.06. As regression slopes were close to unity it can be deduced that corrected peak height values from a DNA pool are unbiased estimates of actual allele frequencies. With standard error of the y-intercept of 0.21, the 95% confidence interval of allele frequency is 0.42 alleles or 1% in a pool of 40 chromosomes. Thus, it would be possible to detect an allele with a frequency of greater than 1% within the pool.

Alleles↗
PubMed2006

On the use of zero-inflated and hurdle models for modeling vaccine adverse event count data.

We compared several modeling strategies for vaccine adverse event count data in which the data are characterized by excess zeroes and heteroskedasticity. Count data are routinely modeled using Poisson and Negative Binomial (NB) regression but zero-inflated and hurdle models may be advantageous in this setting. Here we compared the fit of the Poisson, Negative Binomial (NB), zero-inflated Poisson (ZIP), zero-inflated Negative Binomial (ZINB), Poisson Hurdle (PH), and Negative Binomial Hurdle (NBH) models. In general, for public health studies, we may conceptualize zero-inflated models as allowing zeroes to arise from at-risk and not-at-risk populations. In contrast, hurdle models may be conceptualized as having zeroes only from an at-risk population. Our results illustrate, for our data, that the ZINB and NBH models are preferred but these models are indistinguishable with respect to fit. Choosing between the zero-inflated and hurdle modeling framework, assuming Poisson and NB models are inadequate because of excess zeroes, should generally be based on the study design and purpose. If the study's purpose is inference then modeling framework should be considered. For example, if the study design leads to count endpoints with both structural and sample zeroes then generally the zero-inflated modeling framework is more appropriate, while in contrast, if the endpoint of interest, by design, only exhibits sample zeroes (e.g., at-risk participants) then the hurdle model framework is generally preferred. Conversely, if the study's primary purpose it is to develop a prediction model then both the zero-inflated and hurdle modeling frameworks should be adequate.

Adolescent↗
PubMed2006

Design of vaccine equivalence/non-inferiority trials with correlated multiple binomial endpoints.

Immunogenicity trials that study the immune responses to vaccination are often used in the vaccine development process as alternatives to clinical efficacy trials. The comparisons of immune responses among various treatment groups are conducted in a non-inferiority or equivalence framework. When there exists a level of immune response that correlates with protection against disease, it is of interest to compare the proportion of responders as defined as response above a specific level or as a predefined increase in immune levels for post-vaccination levels above pre-vaccination levels. Since vaccines often contain several antigens, the correlations between the immune responses need to be taken into account in the analysis. In this paper, we describe appropriate testing methods for demonstrating the non-inferioritylequivalence of two treatments on each of the binomial endpoints. We conduct a comprehensive simulation study to shed light on how the Type I error and power are affected and to what extent when correlated multiple binomial endpoints are present in the vaccine trials. We also illustrate the computation of power for assessment of non-inferioritylequivalence in real studies.

Adolescent↗
PubMed1997

Application of CUSUM technique and beta-binomial model in monitoring adverse drug reactions.

The cumulative sum (CUSUM) technique is applied to monitor spontaneous reports of adverse drug reactions (ADRs). The beta-binomial model, as suggested by Moussa (2), was used to fit the observed proportion of upper gastrointestinal bleeding, perforation, and ulcer (UGIBPU) for drug A, a nonsteroidal anti-inflammatory drug (NSAID). ADRs reported directly by physicians and manufacturers from the third quarter of 1982 through the fourth quarter of 1985 were analyzed. The model estimates the proportion of UGIBPUs for drug A, expressed as a fraction of all UGIBPUs for NSAIDs. To illustrate the procedure, estimated mean proportion of UGIBPUs for drug A and all NSAIDs was computed for directly reported physician and manufacturer ADRs. The beta-binomial model leads to estimates of 0.096 for directly reported physician ADRs compared to 0.039 for directly reported manufacturer ADRs. The difference is statistically significant (p < 0.025) by the method of maximum likelihood applied to the beta-binomial model. Moussa also suggested the use of this model for signaling important new ADRs. For these data on NSAIDs, the CUSUM method is less likely to signal an alarm than the approaches suggested by Mandel (5) and Patwary (4).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Sample size determination for controlling the upper confidence limit of incidence rate of a binomial endpoint.

Assume that in a comparative clinical study the primary endpoint is a binary event, such as life or death. A new treatment or therapy is tested for a significant reduction of the incidence of the binary event compared with a control group. Another objective is to ensure that the incidence in the new treatment group is below some clinically acceptable value. This is done by calculating the exact upper 95% confidence limit for the probability of the event. The study is considered successful if the upper confidence limit is lower than a historical threshold, as well as if there is a significant reduction in the incidence of the event by the new treatment. In this article, we provide an exact method for calculating the sample size so that there will be adequate power to ensure that the exact upper confidence limit is below the threshold. Based on this we can design a study to achieve both objectives.

Binomial Distribution↗
PubMed1998

The conditional binomial test revisited for clinical trials.

McNemar's test is used to test the hypothesis that one treatment is better than another in a matched-pair design for binary outcomes. The conditional binomial test in such a matched-pair design is the exact McNemar test. However, in many clinical trials, one wants to establish equivalency between two treatments. We discuss how to use a conditional binomial test to establish equivalency between two treatments in a matched-pair design. Sample size and power determination for each conditional binomial test are calculated. Some statistical properties of the tests are analyzed through Monte Carlo simulation.

Binomial Distribution↗
PubMed2003

Modeling accident occurrence at signalized tee intersections with special emphasis on excess zeros.

In implementing effective remedial treatments at hazardous intersections, it often is necessary to identify the geometric and traffic factors that lead to accident occurrence. However, one particular problem frequently encountered in accident studies is how to distinguish virtually safe intersections with little likelihood of accident occurrence from those that have happened to have no accident due to the random process. To deal with this problem, the "excess" records of zero accident, the zero-inflated negative binomial was used to assign the probability to the accident outcome. Accident data at 104 signalized tee intersections in Singapore over a period of 9 years were employed for model development. The model indicates that uncontrolled left-turn slip road, permissive right-turn phase, existence of a horizontal curve, short sight distances, large number of signal phases, total approach volume, and left-turn volume may increase accident occurrence. On the other hand, right-turn channelization, acceleration section on the left-turn lane, median railings, and more than 5% approach gradient may reduce accident occurrence. Moreover, there is a trend of reducing accidents over the years.

Accidents, Traffic↗