Analysis of covariance in agronomy and crop research

2011 ◽  
Vol 91 (4) ◽  
pp. 621-641 ◽  
Author(s):  
Rong-Cai Yang ◽  
Patricia Juskiw
Keyword(s):  
Regression Analysis ◽  
Spatial Variation ◽  
Mixed Models ◽  
Mixed Model ◽  
Statistical Technique ◽  
Analysis Of Covariance ◽  
Statistical Software ◽  
Mixed Model Analysis ◽  
Crop Research ◽  
Advanced Topic

Yang, R.-C. and Juskiw, P. 2011. Analysis of covariance in agronomy and crop research. Can. J. Plant Sci. 91: 621–641. Analysis of covariance (ANCOVA) is a statistical technique that combines the methods of the analysis of variance (ANOVA) and regression analysis. However, ANCOVA is an advanced topic that often appears towards the end of many textbooks, and thus, it is either taught cursorily or ignored completely in many statistics classes. Additionally, many elaborated applications of ANCOVA to agronomy and crop research along with uses of the latest statistical software are rarely described in textbooks or classes. The objectives of this paper are to provide an overview on conventional ANCOVA and to introduce more advanced uses of ANCOVA under mixed models. We describe three elaborate applications including (i) the use of ANCOVA for dissecting dosage responses for different treatments, (ii) stability of treatments across multiple environments and (iii) removal of spatial variation that is not effectively controlled by blocking. These analyses illustrate that ANCOVA is either a simpler analysis or provides more information than conventional statistical methods. We provide a technical appendix ( Appendix A ) on principles and theory underlying mixed-model analysis of ANCOVA along with SAS programs ( Appendix B ) for more uses and in-depth understanding of this powerful technique in agronomy and crop research.

Exceptional Experiences Following Exposure to a Sham “God Helmet”: Evidence for Placebo, Individual Difference, and Time of Day Influences

2017 ◽  
Vol 39 (1) ◽  
pp. 44-87 ◽  
Author(s):  
Christine Simmonds-Moore ◽  
Donadrian L. Rice ◽  
Chase O’Gwin ◽  
Ron Hopkins
Keyword(s):  
Mixed Model ◽  
Time Of Day ◽  
Neural Stimulation ◽  
Analysis Of Covariance ◽  
Subjective Experiences ◽  
Mixed Model Analysis ◽  
Temporal Lobes ◽  
Coding Scheme ◽  
Paranormal Belief ◽  
Inductive Thematic Analysis

It has been claimed that applying weak complex electromagnetic patterns to the temporal lobes in a “God Helmet” stimulates the intrusion of right-hemispheric processes to awareness, resulting in exceptional experiences (ExEs). We explored the roles of wearing a sham helmet, time of day, and individual differences (paranormal belief, synesthesia, locus of control, hyperesthesia, and prior anomalous experiences) in alterations in consciousness and ExEs in the absence of neural stimulation. Thirty-two skeptics and 35 paranormal believers completed baseline, sham (morning), and sham (afternoon) conditions. Participants relaxed in a Faraday chamber for 30 minutes. Exit interviews explored subjective experiences and participants completed the Phenomenology of Consciousness Inventory (PCI). A mixed-model analysis of covariance found that believers scored higher than skeptics on some PCI dimensions, there was no influence of study conditions on PCI scores, and there was no interaction between belief and study conditions. An inductive thematic analysis identified a coding scheme for ExE. Believers reported more ExEs than skeptics. Regression models supported roles for hyperesthesia in alterations in consciousness and synesthesia in ExEs.

Existence of Mixed Emotions During Consumption of a Sporting Event: A Real-Time Measure Approach

2017 ◽  
Vol 31 (4) ◽  
pp. 360-373 ◽  
Author(s):  
Jun Woo Kim ◽  
Marshall Magnusen ◽  
Hyun-Woo Lee
Keyword(s):  
Real Time ◽  
Mixed Model ◽  
Experimental Studies ◽  
Analysis Of Covariance ◽  
Continuous Measure ◽  
Mixed Emotions ◽  
Mixed Model Analysis ◽  
Consumer Emotions ◽  
Game Outcome ◽  
Sport Consumer Behavior

Investigating the existence of mixed emotions within a sport consumer behavior context is the purpose of this study. Two experimental studies with a 4 (game outcome) × 2 (response format) mixed model analysis of covariance were implemented. The authors tested concurrence of two opposite emotions in Study 1 by asking subjects to complete an online continuous measure of happiness/sadness. Subjects reported more mixed emotions while watching a conflicting game outcome, such as a disappointing win and relieving loss, than during a straight game outcome. In Study 2, real-time-based measures of sport consumer emotions appear to have greater validity than recall-based measures of sport consumer emotions. Subjects with real-time-based measures were less likely to report a straight loss as positive and a straight win as negative than those with the retrospective measure. This study provides evidence of mixed emotions; specifically, happiness and sadness can co-occur during sports consumption.

scholarly journals Diallel mixed-model analysis of papaya fruit deformities

2017 ◽  
Vol 47 (5) ◽  
Author(s):  
Deisy Lúcia Cardoso ◽  
Marcelo Vivas ◽  
Fernanda Oliveira Pinto ◽  
Alexandre Pio Viana ◽  
Antonio Teixeira do Amaral Júnior ◽  
...  
Keyword(s):  
Combining Ability ◽  
Mixed Models ◽  
Mixed Model ◽  
Model Analysis ◽  
Specific Combining Ability ◽  
Mixed Model Analysis

ABSTRACT: Changes in the shape of fruits from hermaphrodite flowers due to floral anomalies are quite common. The aim of this study was to estimate the effects of the general and specific combining ability on the proportions of normal and deformed (carpelloid and pentandric) papaya fruits in hermaphrodite plants using mixed models. The ‘JS12-N’, ‘Waimanalo’ and ‘Golden’ parents showed the potential to decrease the number of deformed fruits. In contrast, the ‘Maradol x JS12-N’, ‘Maradol x Waimanalo’, ‘Maradol x Golden’, ‘JS12-N x JS12-4’, ‘JS12-N x Sekati’, ‘JS12-N x Waimanalo’, ‘Waimanalo x JS12-N’, ‘Waimanalo x JS12-4’, ‘Waimanalo x Golden’, ‘Waimanalo x Sunrise Solo 72/12’, ‘Golden x Maradol’, ‘Golden x JS12-N’, ‘Golden x Sekati’, ‘Golden x Waimanalo’ and ‘São Mateus x JS12-N’ hybrids have the potential to increase the number of marketable fruits while decreasing the number of carpelloid and pentandric fruits.

Plaque Removal Efficacy of a Prototype Manual Toothbrush versus an ADA Reference Manual Toothbrush with and without Dental Floss

2005 ◽  
Vol 6 (3) ◽  
pp. 1-13 ◽  
Author(s):  
Aaron R. Biesbrock ◽  
Robert D. Bartizek ◽  
Samer A. Bsoul ◽  
Geza T. Terezhalmy
Keyword(s):  
Mixed Model ◽  
Mean Difference ◽  
Analysis Of Covariance ◽  
Plaque Score ◽  
Dental Floss ◽  
Mixed Model Analysis ◽  
Plaque Removal ◽  
Gingival Margin ◽  
Manual Toothbrush ◽  
Reference Manual

Abstract Objective The objective of this study was to compare the plaque removal efficacy of a prototype manual Deep Clean toothbrush versus an American Dental Association (ADA) manual toothbrush and the ADA manual toothbrush in conjunction with floss. Methods This study was a randomized, examiner-blind, six-period cross-over, single-center study conducted in 60 adult subjects that examined plaque removal with a prototype Deep Clean manual toothbrush, an ADA reference manual toothbrush, and an ADA reference manual toothbrush followed by floss. During the course of this study, subjects used each treatment two times. Plaque was scored before and after brushing using the Rustogi Modification of the Navy Plaque Index. A mixed model analysis of covariance (ANCOVA) for a crossover design with baseline plaque score as the covariate was applied to the baseline minus one-minute post-brushing differences in average whole-mouth plaque scores. Supplemental analyses were also performed using the ANCOVA model separately for average gingival margin scores and for average interproximal scores, using the appropriate baseline score as the covariate. All comparisons were two-sided at the 0.05 level of significance. Results The prototype Deep Clean manual toothbrush delivered an adjusted (via ANCOVA) mean difference between baseline and post-brushing plaque scores of 0.245, while the ADA manual toothbrush plus floss delivered an adjusted mean difference of 0.207 versus 0.196 for the ADA manual toothbrush alone. The prototype Deep Clean manual toothbrush demonstrated a statistically significantly greater reduction in plaque than the ADA manual toothbrush plus floss (p<0.001), which in turn had a statistically significantly greater reduction in plaque than the ADA manual toothbrush alone (p<0.001). The prototype Deep Clean manual toothbrush group had, on average, 25.2% and 18.3% greater plaque removal scores than the ADA manual toothbrush alone and the ADA manual toothbrush plus floss groups, respectively. Results for the interproximal and gingival margin regions also demonstrated statistically significantly (p<0.001) greater plaque removal for the prototype Deep Clean manual toothbrush group relative to the other groups. Conclusions The prototype manual Deep Clean toothbrush was found to deliver greater plaque removal by 25.2% and 18.3% compared to the control manual toothbrush group (ADA reference manual toothbrush) and ADA manual toothbrush plus floss group. Citation Terézhalmy GT, Bsoul SA, Bartizek RD, Biesbrock AR. Plaque Removal Efficacy of a Prototype Manual Toothbrush versus an ADA Reference Manual Toothbrush with and without Dental Floss. J Contemp Dent Pract 2005 August;(6)3:001-013.

scholarly journals Association between housing and health of refugees and asylum seekers in Germany: explorative cluster and mixed model analysis

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Verena Dudek ◽  
Oliver Razum ◽  
Odile Sauzet
Keyword(s):  
Mental Health ◽  
Regression Analysis ◽  
Health Disparities ◽  
Physical Health ◽  
Asylum Seekers ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Bivariate Analysis ◽  
Cross Sectional ◽  
Mixed Model Analysis

Abstract Background Accommodation for asylum seekers and refugees (ASR) in Germany differs in many ways depending on a range of political, structural, social, and environmental factors. These contextual differences present a challenge for assessing health impacts of refugee accommodation. We aimed to devise a broad typology of refugee accommodation that allows to assess associations between housing and health of ASR. Methods We performed a cluster analysis of population-based, cross-sectional secondary data in Germany to identify clusters of refugee accommodation. We then assessed health disparities across clusters by performing bivariate analysis and linear mixed model regression analysis. Results We identified four clusters, three of them reflected different types of private accommodation and one pointed to collective accommodation. The collective accommodation cluster clearly differed from the private accommodation clusters in terms of space, area, level of restrictions, social connections and respondent satisfaction. Across private accommodation clusters we also found differences in space, area, and level of restrictions. In regression analysis, belonging to one of the private accommodation cluster was significantly associated with better mental health compared to belonging to the collective accommodation cluster. Physical health was significantly lower in one private accommodation cluster characterized by poor access to public transport and a higher level of restrictions compared to a private accommodation cluster showing better connections and a lower level of restrictions. Conclusion We demonstrate that unfavourable conditions cluster in collective accommodation with negative outcomes for mental health but not for physical health. We also found health disparities across types of private accommodation. We conclude that housing plays a role in the production of health inequalities in ASR but needs to be assessed in a differentiated, multidimensional way.

İŞE BAĞLILIĞIN TÜKENMİŞLİK VE DEPRESYON DÜZEYLERİ ÜZERİNDEKİ ETKİLERİ: SAĞLIK ÇALIŞANLARI ÜZERİNDE BİR ARAŞTIRMA

2014 ◽  
Vol 1 (2) ◽  
pp. 206
Author(s):  
Haluk TANRIVERDİ ◽  
Mucize SARIHAN
Keyword(s):  
Regression Analysis ◽  
Correlation Analysis ◽  
Health Workers ◽  
Personal Information ◽  
Depression Scale ◽  
Work Commitment ◽  
Statistical Software ◽  
Research Hospital ◽  
Training And Research

The main purpose of this study is to examine the effects of health workers’ levels of work commitment on the levels of depression and burnout.  Having this purpose in mind, a questionnaire consisting of personal information form, work commitment scale, burnout scale and depression scale was conducted with 266 health workers of İstanbul Kartal Training and Research Hospital in May 2013. Data obtained from questionnaires were analyzed by SPSS 17,0 statistical software. Correlation analysis was utilized in order to determine the relationships among work commitment, burnout and depression levels of health workers whereas regression analysis was utilized in order to determine the effects of health workers’ levels of work commitment on the levels of depression and burnout. According to the results, it has been found that there are statistically relevant relationships among work commitment, burnout and depression levels of health workers. It has been concluded that the more health workers’ levels of work commitment increase, their levels of depression and burnout decrease.

scholarly journals Reducing Aggression by Developing Emotional and Inhibitory Control

2021 ◽  
Vol 18 (10) ◽  
pp. 5263
Author(s):  
Miriam Romero-López ◽  
María Carmen Pichardo ◽  
Ana Justicia-Arráez ◽  
Judit Bembibre-Serrano
Keyword(s):  
Psychosocial Development ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Generalized Linear Mixed Model ◽  
Emotional Control ◽  
Control Group ◽  
Post Intervention ◽  
Mixed Model Analysis ◽  
Intervention Measures ◽  
Experimental Group

The objective of this study is to measure the effectiveness of a program on improving inhibitory and emotional control among children. In addition, it is assessed whether the improvement of these skills has an effect on the reduction of aggressive behavior in pre-school children. The participants were 100 children, 50 belonging to the control group and 50 to the experimental group, aged between 5 and 6 years. Pre-intervention and post-intervention measures of inhibitory and emotional control (BRIEF-P) and aggression (BASC) were taken. A Generalized Linear Mixed Model analysis (GLMM) was performed and found that children in the experimental group scored higher on inhibitory and emotional control compared to their peers in the control group. In addition, these improvements have an effect on the decrease in aggressiveness. In conclusion, preventive research should have among its priorities the design of such program given their implications for psychosocial development.

scholarly journals PSX-7 Effect of varying levels of hempseed meal supplementation on animal performance, rumen fermentation, and blood metabolites of growing meat goats

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 459-460
Author(s):  
Frank W Abrahamsen ◽  
Nar Gurung ◽  
Woubit Abdela ◽  
Gopal Reddy ◽  
Kim Mullenix
Keyword(s):  
Mixed Model ◽  
Average Daily Gain ◽  
Live Weight ◽  
Blood Chemistry ◽  
Optimal Level ◽  
Rumen Fermentation ◽  
Serum Glucose ◽  
Mixed Model Analysis ◽  
Meat Goats ◽  
Significant Difference

Abstract Hempseed meal (HSM) is a byproduct of hemp oil production and is high in crude protein, fiber, and fat, making it a potential feedstuff for ruminants. The objective of this study was to evaluate the effect of HSM supplementation on growth performance, rumen fermentation and blood chemistry profile of growing meat goats. Forty castrated, Boer cross goats were randomly assigned to one of the four treatments (n = 10): control, 10%, 20%, and 30% HSM supplementation. Data collected over a period of a 60-day feeding trial were analyzed utilizing the mixed model analysis function of SYSTAT, version 13. The result revealed total live weight gain decreased with the increasing levels of HSM supplementation 10.75, 9.53, 8.48, and 7.80 kg, for 0, 10, 20, and 30%, respectively. Average daily gain followed the same trend 0.179, 0.159, 0.141, and 0.13 kg, with a significant difference (P &lt; 0.05) observed between the control and 30 % supplementation. Conversely, feed to gain ratio increased with the increasing levels of supplementation 9.0, 10.2, 11.9, 12.2, likewise a significant difference was observed (P &lt; 0.05) between the control and 30% supplementation. Acetic, propionic, butyric, valeric, iso-valeric, and iso-butyric acid concentrations as well as the total VFA concentration decreased significantly (P &lt; 0.05) with the increasing level of supplementation. Acetic to propionic acid ratios increased with increasing level of supplementation 3.43, 4.36, 4.52, and 4.59, significant differences (P &lt; 0.05) were observed between control-20% and 30% HSM group. Serum glucose concentration decreased with an increasing rate of HSM supplementation while BUN concentration increased with no significant differences. These findings provide new insights into the feeding value of HSM for meat goats; however, further research needs to be conducted to determine the optimal level of supplementation.

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