Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Statistics”

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 91 records · Page 5Linked to original sources
PubMed1993

[Population statistics in Cyprus: in the mist of statistics].

The authors examine issues concerning population statistics in Cyprus since the Turkish invasion of 1974 and the political division of the island, particularly how political considerations affect population data. "The article follows two objectives: First, to uncover the motives, strategies and techniques of statistical and argumentative manipulation. Second, the authors try to draw a realistic picture of recent demographic developments in Cyprus by using all available data as objectively as possible." Particular attention is given to population trends in the Turkish-controlled part of the island. The authors conclude that "the demographic question until today represents one of the major obstacles in the search for a political solution of the Cyprus problem." (SUMMARY IN ENG)

Asia↗
PubMed1989

[Cause od death statistics and death certificate documentation. 1. Historical development of cause of death statistics of fetal death, infants and children and current regulations in the GDR].

After having described the beginnings of documentation and statistics of causes of death of newborns and children the development of this branch of medical statistics in the GDR and the introduction of a special death certificate in 1961 is dealt with. To help obstetricians, perinatologists and pediatrists to tackle the problem of documentation of the causes of death of stillborns and newborns the 9th revision of ICD, the nowadays valid death certificate and special rules of signing are explained to avoid mistakes, which are often met with in the daily practice.

Cause of Death↗
PubMed1995

Conventional statistics and useful statistics.

Differences between conventional statistical methods and more useful, modern methods are demonstrated using a statistical analysis of data from therapeutic research in rheumatology. The conventional methods, t-test and graphs of mean values and the boxplot, detect almost no differences between treatment groups. A more recent procedure for analysing group differences is the Wilcoxon-Mann-Whitney test. The associated graphs are based on the cumulative distribution function of the two treatment groups and the synthetic Receiver Operating Characteristic (ROC). Special differences, namely baseline dependencies, can be visualized in this way.

Adjuvants, Immunologic↗
PubMed2005

Diagnostic performance of 18F-FDG PET and ictal 99mTc-HMPAO SPET in pediatric temporal lobe epilepsy: quantitative analysis by statistical parametric mapping, statistical probabilistic anatomical map, and subtraction ictal SPET.

We investigated the diagnostic performance of 18F-FDG PET and ictal (99m)Tc-HMPAO SPET in pediatric temporal lobe epilepsy (TLE). Twenty-one pediatric TLE patients were enrolled in this study. Their diagnoses were confirmed by histology and post-surgical outcome (Engel class I or II). The patients' ages were 18 or younger (15+/-3 years). Of the 21 patients, 21 patients underwent 18F-FDG PET scan and 15 underwent ictal (99m)Tc-HMPAO SPET. Preoperative PET and/or ictal SPET images were reviewed by simple visual assessment and by statistical parametric mapping (SPM). Asymmetric indices (AI) were calculated using statistical probabilistic anatomical map (SPAM) on 18F-FDG PET. In nine patients who underwent both ictal and interictal SPET, SISCOM (subtraction ictal SPET coregistered to MR template) was performed. PET correctly localized epileptogenic zones in 20 of 21 (95%) by visual assessment. SPM analysis of PET correctly localized epileptogenic zones in 18 of 21 (86%). Ictal SPET correctly localized epileptogenic zones in 12 of 15 (80%) by visual assessment. SPM analysis of ictal SPET correctly localized epileptogenic zones in 12 of 15 (80%). SISCOM correctly localized 8 of 9 (89%), which was equal to that of visual assessment of ictal SPET. The AIs of the temporal lobes by PET were -15+/-8.4 in the left and 9.9+/-8.9 in the right TLE (normal control: -2.9+/-2.8), and correctly localized epileptogenic zones in all cases. As is found in adult TLE, PET and ictal SPET efficiently localized epileptogenic zones in pediatric TLE. SPM analysis of PET or ictal SPET could be used as an aid to visual assessment. Moreover, SISCOM was equal visual assessment of ictal SPET images in terms of lesion localizations.

Adolescent↗
PubMed2005

Statistical vs. non-statistical deactivation pathways in the UV photo-fragmentation of protonated tryptophan-leucine dipeptide.

The excited state dynamics of protonated tryptophan-leucine ions WLH+, generated in an electrospray source, is investigated by photo-induced fragmentation in the gas phase, using femtosecond laser pulses. Two main features arise from the experiment. Firstly, the initially excited pipi* state decays very quickly with 2 time constants of 1 and 10 ps. Secondly, the transient signals recorded on different fragments are not the same which indicates two competing primary fragmentation processes. One involves a direct dissociation from the excited state that gives evidence for a non-statistical deactivation path. The other is attributed to a statistical decay following internal conversion to the ground electronic surface.

Dipeptides↗
PubMed2005

Acceleration statistics as measures of statistical persistence of streamlines in isotropic turbulence.

We introduce the velocity Vs of stagnation points as a means to characterize and measure statistical persistence of streamlines. Using theoretical arguments, direct numerical simulations (DNS), and kinematic simulations (KS) of three-dimensional isotropic turbulence for different ratios of inner to outer length scales L/eta of the self-similar range, we show that a frame exists where the average Vs = 0 , that the rms values of acceleration, turbulent fluid velocity, and Vs are related by La'/u'2 approximately (V's/u')(L/eta)(2/3+q) , and that V's/u' approximately (L/eta)q with q = -1/3 in Kolmogorov turbulence, q = -1/6 in current DNS, and q = 0 in our KS. The statistical persistence hypothesis is closely related to the Tennekes sweeping hypothesis.

Journal Article↗
PubMed2006

The potential of feature selection by statistical techniques and the use of statistical classifiers in the discrimination of benign from malignant gastric lesions.

The objective of this study was the investigation of the potential value of morphometry, feature selection and statistical classifiers techniques, such as neural networks, for the classification of benign from malignant gastric nuclei and cases. One hundred and twenty gastric smears, routinely processed and stained by Papanicolaou technique, were analyzed by a customized image analysis system. Data from half of the cases were selected to form the training set, while the remaining data formed the test set. A feature selection technique was applied in order to identify the most important nuclear features, which were used in a second stage by statistical classifiers to classify a nucleus as benign or malignant. Using the classifier results for the nuclear classification, a method to classify each individual patient was developed. The performance of the proposed method was validated through the test set. The technique described in this report produces significant results at the nuclear and patient level and promises to be a powerful assistance tool for everyday cytological laboratory routine.

Anthropometry↗
PubMed1999

[Clinical statistics at the urological clinic of Sanjukai Hospital--statistics on new outpatients over the last five years].

We herein report the clinical statistics on new outpatients over five years from 1994 at our hospital. The average number of new outpatients per year was 8,534.4 (8,366-8,658) and there was only a slight variation in the number over the last five years. The male to female ratio was 1.61:1. Twenty-one percent of the outpatients were referred to us by other sources. The representative operations on outpatients were circumcision, vasectomy, resection of condylomas and resection of caruncles. A statistical study was made on new outpatients according to the international classification of disease. There were 197.0 (2.3%) malignant urogenital tumors per year. There was a tendency for sexually transmitted diseases to increase over the last five years. In males, the major diseases were upper urinary tract stones (23-27%), benign prostatic hypertrophy (19-26%) and prostatitis (15-24%). In females, they were cystitis (57-59%), upper urinary tract stones (17-18%) and neurogenic bladder (3-4%). We conclude that our hospital plays a major role as a private urological hospital.

Adult↗
PubMed1998

International comparative analysis of injury mortality. Findings from the ICE on injury statistics. International Collaborative Effort on Injury Statistics.

OBJECTIVE: This report investigates international differences in injury mortality rates among 11 of the countries participating in the International Collaborative Effort on Injury Statistics. METHODS: The cause, intent, and age-specific injury mortality rates are calculated and presented from Australia, Canada, Denmark, England & Wales, France, Israel, New Zealand, The Netherlands, Norway, Scotland, and the United States. Data are presented by cause (or mechanism) and intent (or manner of death) according to the matrix framework for presenting injury mortality statistics published in August 1997. The benefits of this matrix approach to investigating injury mortality are explained with numerous examples. RESULTS: Injury death rates are higher in France and Denmark and lower in England & Wales, Israel, and The Netherlands than elsewhere. New Zealand, the United States, and Norway had similar average annual injury death rates of 56-57 per 100,000 population. As an example of the benefit of presenting data in the matrix framework, the total poisoning death rate in Denmark for all categories of intent (13 per 100,000) is about twice the rate in the United States. Unintentional poisoning death rates, however, are similar in the United States and Denmark (about 4 per 100,000) and are higher than elsewhere. However, the suicide poisoning death rate in Denmark is 3 times the rate in the United States. CONCLUSION: Using these results, the ICE on Injury will be investigating death registration practices in each of the countries to better understand international variation in injury mortality due to reporting or registration procedures.

Accidents↗
PubMed1998

Statistical Inference (Part 3): Statistical Hypothesis Testing and Confidence Interval Estimation.

An association between an independent and a dependent variable found in a study may have several explanations, including chance (i.e., random error). This article presents two approaches to assess the role played by chance in an association: confidence interval estimation and statistical hypothesis testing. Statistical hypothesis testing estimates the probability (i.e., the P value) of getting a difference as large or larger than the one observed in a specific study assuming the absence of association. Confidence intervals are estimates of the range of values that are expected to include the actual parameter with a certain probability, or confidence level (often 0.95 or 95%).

Journal Article↗
PubMed1995

[Clinical statistics at the urological clinic of Sanjukai Hospital--statistics on new outpatients during the last five years].

We report the clinical statistics of new outpatients for five years since 1989 at our hospital. The average total number of new outpatients in a year was 8309.8 (8122-8691) and new outpatients tended to show little change. The male to female ratio was 1.57:1, and 24.3% of the outpatients were referred to us by others sources. The representative operations on outpatients were circumcision, vasectomy, resection of condyloma and resection of caruncle. A statistical study was made on new outpatients according to the international classification of disease. There were 140.6 (1.97%) malignant urogenital tumors per year. Sexually transmitted diseases showed a tendency to increase for the last five years. In males the major disease was upper urinary tract stone (21-24%), prostatistis (21-24%) and benign prostatic hypertrophy (17-20%) and in females they were cystitis (58-61%), upper urinary tract stone (15-17%) and pyelonephritis (3-4%). We conclude that our hospital plays a major role as a private urological hospital.

Female↗
PubMed1996

The statistical analysis of kappa statistics in multiple samples.

Methods are presented for assessing and comparing the results of k > or = 2 independent samples of measured agreement or concordance, where in each sample a given member of a pair of observations is classified according to the presence or absence of a binary trait. Examples include the assessment of interobserver agreement across different groups of patients in a clinical study, investigations of sibling concordance across different genetic groups, and meta-analyses of observer agreement across different studies. The methodology described is based on application of goodness-of-fit theory to testing hypotheses concerning kappa statistics. Partitioning methods allow a variety of hypotheses to be tested, including an assessment of the degree of agreement within each sample, a testing procedure based on the pooled data, and a test of heterogeneity that may be used to assess the validity of pooling across samples. Three examples are given.

Humans↗
PubMed1990

Statistical significance and statistical power in hypothesis testing.

Experimental design requires estimation of the sample size required to produce a meaningful conclusion. Often, experimental results are performed with sample sizes which are inappropriate to adequately support the conclusions made. In this paper, two factors which are involved in sample size estimation are detailed--namely type I (alpha) and type II (beta) error. Type I error can be considered a "false positive" result while type II error can be considered a "false negative" result. Obviously, both types of error should be avoided. The choice of values for alpha and beta is based on an investigator's understanding of the experimental system, not on arbitrary statistical rules. Examples relating to the choice of alpha and beta are presented, along with a series of suggestions for use in experimental design.

Research Design↗
PubMed1998

Statistical methods in epidemiology: a comparison of statistical methods to analyze dose-response and trend analysis in epidemiologic studies.

Evaluation of various statistical methods to describe accurately associations between exposures and disease are constantly being explored. Spline regression has been suggested as an alternative to using categorized variables in studies of disease etiology, as it uses all data points to estimate the shape of the association between a given exposure and disease outcome. It has been proposed that this method is especially beneficial when associations are concentrated in a small range of the overall distribution of the exposure. In this study, we use data from a large case-control study of colon cancer to evaluate associations obtained from logistic regression models that use spline regression for main exposure and confounder effects with those that use categorized variables for main exposure. Our results show that for variables for which the association appears to be linear, such as body size and dietary intake of calcium, fiber, and cholesterol, associations are similar when estimates are generated from spline or categorized variable models. For other variables, such as total energy intake, for which associations appear to be strongest in the upper end of the distribution, estimates of association appear to be conservative when using categorized variables. The data also suggest that selection of cut points for the categorized variables may have an impact on the associations observed. Spline regression appears to be useful to estimate the shape of the association between a given exposure and disease and may provide guidance as to the appropriateness of using categorized variables. The risk estimates from spline regression appear to be similar to those from traditional categorical methods. When effects are large or rapidly changing, spline models may more appropriately describe the association.

Adult↗
PubMed2003

Statistical approaches for assessing the relative validity of a food-frequency questionnaire: use of correlation coefficients and the kappa statistic.

OBJECTIVE: To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR). DESIGN: Subjects completed the Scottish Collaborative Group FFQ and carried out a 4-day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients, the percentages of subjects classified into the same and opposite thirds of intake, and Cohen's weighted kappa. SUBJECTS: Forty-one men, mean age 36 (range 21-56) years, and 40 women, mean age 33 (range 19-58) years, recruited from different locations in Aberdeen, Scotland. RESULTS: Spearman correlation coefficients tended to be lower than Pearson correlation coefficients, and were above 0.5 for 10 of the 27 nutrients in men and 17 of the 27 nutrients in women. For nutrients with Spearman correlation coefficients above 0.5, the percentage of subjects correctly classified into thirds ranged from 39 to 78%, and weighted kappa values ranged from 0.23 to 0.66. CONCLUSIONS: Both Spearman correlation coefficients and weighted kappa values are useful in assessing the relative validity of estimates of nutrient intake by FFQs. Spearman correlation coefficients above 0.5, more than 50% of subjects correctly classified and less than 10% of subjects grossly misclassified into thirds, and weighted kappa values above 0.4 are recommended for nutrients of interest in epidemiological studies.

Adult↗
PubMed2003

Advanced statistics: applying statistical process control techniques to emergency medicine: a primer for providers.

Emergency medicine faces unique challenges in the effort to improve efficiency and effectiveness. Increased patient volumes, decreased emergency department (ED) supply, and an increased emphasis on the ED as a diagnostic center have contributed to poor customer satisfaction and process failures such as diversion/bypass. Statistical process control (SPC) techniques developed in industry offer an empirically based means to understand our work processes and manage by fact. Emphasizing that meaningful quality improvement can occur only when it is exercised by "front-line" providers, this primer presents robust yet accessible SPC concepts and techniques for use in today's ED.

Emergency Medicine↗