The Non-Central Chi-Squared and Beta Distributions

Biometrika ◽  
1963 ◽  
Vol 50 (3/4) ◽  
pp. 542 ◽  
Author(s):  
G. A. F. Seber
Keyword(s):  
Beta Distributions ◽  
Chi Squared

The non-central chi-squared and beta distributions

Biometrika ◽  
1963 ◽  
Vol 50 (3-4) ◽  
pp. 542-544 ◽  
Author(s):  
G. A. F. SEBER
Keyword(s):  
Beta Distributions ◽  
Chi Squared

Risk of venous thromboembolism following surgical treatment of superficial venous incompetence

VASA ◽  
2017 ◽  
Vol 46 (6) ◽  
pp. 484-489 ◽  
Author(s):  
Tom Barker ◽  
Felicity Evison ◽  
Ruth Benson ◽  
Alok Tiwari
Keyword(s):  
Venous Thromboembolism ◽  
Varicose Vein ◽  
Lower Incidence ◽  
Varicose Veins ◽  
Secondary Data ◽  
Foam Sclerotherapy ◽  
Increased Risk ◽  
Significant Difference ◽  
Chi Squared ◽  
One Year

Abstract. Background: The invasive management of varicose veins has a known risk of post-operative deep venous thrombosis and subsequent pulmonary embolism. The aim of this study was to evaluate absolute and relative risk of venous thromboembolism (VTE) following commonly used varicose vein procedures. Patients and methods: A retrospective analysis of secondary data using Hospital Episode Statistics database was performed for all varicose vein procedures performed between 2003 and 2013 and all readmissions for VTE in the same patients within 30 days, 90 days, and one year. Comparison of the incidence of VTEs between procedures was performed using a Pearson’s Chi-squared test. Results: In total, 261,169 varicose vein procedures were performed during the period studied. There were 686 VTEs recorded at 30 days (0.26 % incidence), 884 at 90 days (0.34 % incidence), and 1,246 at one year (0.48 % incidence). The VTE incidence for different procedures was between 0.15–0.35 % at 30 days, 0.26–0.50 % at 90 days, and 0.46–0.58 % at one year. At 30 days there was a significantly lower incidence of VTEs for foam sclerotherapy compared to other procedures (p = 0.01). There was no difference in VTE incidence between procedures at 90 days (p = 0.13) or one year (p = 0.16). Conclusions: Patients undergoing varicose vein procedures have a small but appreciable increased risk of VTE compared to the general population, with the effect persisting at one year. Foam sclerotherapy had a lower incidence of VTE compared to other procedures at 30 days, but this effect did not persist at 90 days or at one year. There was no other significant difference in the incidence of VTE between open, endovenous, and foam sclerotherapy treatments.

Bidirectional Associations Between Self-Perceptions of Aging and Processing Speed Across 3 Years

GeroPsych ◽  
2017 ◽  
Vol 30 (2) ◽  
pp. 49-59 ◽  
Author(s):  
Anna L. Seidler ◽  
Julia K. Wolff
Keyword(s):  
Processing Speed ◽  
Personal Growth ◽  
Significant Loss ◽  
Path Model ◽  
Outcome Variable ◽  
Beneficial Effects ◽  
Self Perceptions ◽  
Chi Squared ◽  
Perceptions Of Aging ◽  
Bidirectional Associations

Abstract. Background: Previous studies point to a potential relationship between self-perceptions of aging (SPA) and cognitive performance. However, most of these studies are limited by their experimental design. Previous longitudinal studies looked solely at memory as an outcome variable without examining the directionality of effects. The present study examines the direction of effects between two domains of SPA (personal growth and physical losses) and processing speed (PS). Methods: The sample consists of 8,198 participants of the German Ageing Survey (DEAS), aged between 40 and 93 years. A cross-lagged path model was estimated to examine directions of relationships across 3 years via chi-squared difference tests for each domain of SPA. Results: In the unconstrained models, the effect of SPA domain personal growth in 2008 on PS in 2011 and vice versa were marginally significant. For SPA domain physical losses, the effect of SPA on PS was significant, whereas the other direction of the effect did not reach significance. However, the cross-lagged paths of both domains of SPA on PS and vice versa could be set equal without a significant loss of model fit. The resulting associations indicate a significant bidirectional relationship between both domains of SPA and PS. Discussion and conclusion: This study provides initial evidence that SPA can influence trajectories of cognitive decline and vice versa. The results emphasize the detrimental and beneficial effects that stereotypes can have on individuals and add further evidence to the theory of stereotype embodiment.

Bayesian Diagnostic Probabilities without Assuming Independence of Symptoms

1991 ◽  
Vol 30 (01) ◽  
pp. 15-22 ◽  
Author(s):  
A. Gammerman ◽  
A. R. Thatcher
Keyword(s):  
Abdominal Pain ◽  
Acute Abdominal Pain ◽  
Final Diagnosis ◽  
Bayes Theorem ◽  
Bayes Method ◽  
Hospital Records ◽  
Computer Diagnosis ◽  
Bayes Model ◽  
Chi Squared ◽  
Past Data

The paper describes an application of Bayes’ Theorem to the problem of estimating from past data the probabilities that patients have certain diseases, given their symptoms. The data consist of hospital records of patients who suffered acute abdominal pain. For each patient the records showed a large number of symptoms and the final diagnosis, to one of nine diseases or diagnostic groups. Most current methods of computer diagnosis use the “Simple Bayes” model in which the symptoms are assumed to be independent, but the present paper does not make this assumption. Those symptoms (or lack of symptoms) which are most relevant to the diagnosis of each disease are identified by a sequence of chi-squared tests. The computer diagnoses obtained as a result of the implementation of this approach are compared with those given by the “Simple Bayes” method, by the method of classification trees (CART), and also with the preliminary and final diagnoses made by physicians.

Factors driving changes to remuneration policies in South Africa

2019 ◽  
Vol 39 (2) ◽  
pp. 43-63 ◽  
Author(s):  
Mark Bussin
Keyword(s):  
South Africa ◽  
South African ◽  
Merit Pay ◽  
Drivers Of Change ◽  
Retention Strategies ◽  
Retention Strategy ◽  
Remuneration Policy ◽  
Chi Squared ◽  
Firm Data ◽  
E Mail

This study was conducted in 2012 and replicates Bussin and Huysamen’s (2004) work, conducted in 2003, on remuneration policies. It investigates the factors driving remuneration policy in South Africa and determines whether these factors have changed since 2003. Anonymous e-mail questionnaires were received from 131 senior company representatives. All participating companies were members of the South African Reward Association (SARA) or clients of a large remuneration consulting firm. Data were analysed using a chi-squared test and factor analysis. Results support Bussin and Huysamen’s study, which found that the two main drivers of change in policy were the retention of talented staff and the financial results of the organisation. However, three components of remuneration are receiving greater prominence than they did in 2003: governance in the organisation, merit pay and retention strategies. These findings suggest a greater shareholder expectation that pay should be linked to performance, and that pay acts as a retention strategy for critical staff.

Ethnopharmacological Survey of Medicinal Plants Used in Traditional Treatment of Kidney Diseases in Fez–Meknes Region, Morocco

2019 ◽  
Vol 18 (2) ◽  
pp. 99-114
Author(s):  
M. Chebaibi ◽  
D. Bousta ◽  
I. Iken ◽  
H. Hoummani ◽  
A. Ech-Choayeby ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Medicinal Plants ◽  
Kidney Diseases ◽  
Rank Order ◽  
Pearson Correlation ◽  
Use Value ◽  
Traditional Treatment ◽  
Toxic Plants ◽  
A Value ◽  
Chi Squared

The purpose of this study was to inventory and collect information on plants and mixtures commonly used by herbalists to treat kidney disease in the Fez–Meknes region. We also aimed to compare the results obtained with the results of the other studies and exploit the correlations between different factors. An ethnopharmacological survey was conducted from 289 local herbalists in eight different areas of Fez–Meknes region. Ethnomedicinal uses and ethnobotanical indices were analyzed using quantitative tools, i.e., the total number of citation (TNC), use value (UV), family use value (FUV), fidelity level (FL), and rank order priority (ROP). Statistical analyses such as Pearson correlation and chi-squared test were performed to delineate any correlation. Two hundred and eighty-nine herbalists were questioned. Sixty-nine plant species belonging to 38 families were cited by herbalists for traditional treatment of kidney disease. The highest value of UV was obtained for Herniaria glabra L. (UV = 0.79), and Caryophyllaceae was the family frequently cited (FUV = 0.795). Ammodaucus leucotrichus Coss. & Dur. had the highest value of FL with a value of 100%, and the highest value of ROP was recorded for Herniaria glabra L. (ROP = 91%). Sociodemographic characteristics had a significant impact on the knowledge of toxic plants. Our study has revealed a cultural heritage linked to herbalism and a great wealth of medicinal plants, whose valorization and protection are necessary. Several studies are needed to sensitize herbalists and population on the danger of toxic plants, to extract chemical compounds from the main plants used, and to evaluate their toxicity.

PENERAPAN CHAID DENGAN PENDEKATAN SMOTE PADA KEMATIAN BALITA DI KAWASAN TIMUR INDONESIA TAHUN 2017

2020 ◽  
Vol 2019 (1) ◽  
pp. 357-367
Author(s):  
Isti Samrotul Hidayati ◽  
I Made Arcana
Keyword(s):  
Sampling Technique ◽  
Chi Square ◽  
Interaction Detection ◽  
Chi Squared

Metode Chi-squared Automatic Interaction Detection (CHAID) merupakan metode segmentasi berdasarkan hubungan variabel respon dan penjelas menggunakan uji chi-square, yang dalam penerapannya perlu memperhatikan keseimbangan data untuk meminimalkan kesalahan dalam klasifikasi. Salah satu pendekatan yang dapat digunakan pada data yang tidak seimbang adalah metode Synthetic Minority Over-sampling Technique (SMOTE). Dalam penelitian ini, metode CHAID dengan pendekatan SMOTE diterapkan pada Angka Kematian Balita (AKBa) di Kawasan Timur Indonesia (KTI). Tujuannya adalah untuk mengetahui variabel-variabel yang mencirikan kematian balita berdasarkan metode analisis CHAID yang diterapkan dan membandingkannya dengan pendekatan SMOTE. Hasil perbandingan menunjukkan bahwa pendekatan SMOTE lebih baik digunakan dengan nilai sensitivitas sebesar 48,3% dan nilai presisi sebesar 75,9%. Variabel yang signifikan mencirikan kematian balita di KTI adalah berat badan saat lahir, jenis kelahiran, status bekerja ibu dan kekayaan rumah tangga, dengan karakteristik utama adalah balita yang memiliki berat badan lahir rendah dan terlahir kembar.

Statistical Analysis of the Relationship Between Antioxidant Activity and the Structure of Flavonoid Compounds

2019 ◽  
Vol 70 (9) ◽  
pp. 3103-3107 ◽  
Author(s):  
Ioana Glevitzky ◽  
Gabriela Alina Dumitrel ◽  
Mirel Glevitzky ◽  
Bianca Pasca ◽  
Pavel Otrisal ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Basic Structure ◽  
Oh Groups ◽  
Flavonoid Compounds ◽  
Chi Squared ◽  
Potential Link ◽  
Van Der Waals Surface ◽  
The Relationship ◽  
Phenolic Oh Groups

Using different methods of statistics, this paper aims to highlight the potential link between the antioxidant activity of flavonoids and the corresponding molecular descriptors. By calculating the descriptors (van der Waals surface (A), molar volume (V), partition coefficient (LogP), refractivity (R), polarizability (a), forming heat (Hformation), hydration energy (Ehidr), the dipole moment (mt)), together with antioxidant activities (RSA) calculated or taken from the literature, number of phenolic -OH groups and the presence (2) or absence (1) of C2=C3 double bond) for 29 flavonoid compounds and by intercorrelation between the studied parameters, the link between the number of phenolic groups grafted to the basic structure of flavonoids and their antioxidant activity was confirmed. Simultaneously, by using the chi-squared test and the intercorrelations matrix, a satisfactorily correlation coefficient (r2=0.5678; r=0.7536) between the structure of the flavonoids and their activity was obtained, fact that confirms the correlation of the antioxidant activity with the number of -OH phenolic groups.

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