scholarly journals A Multivariate Variance Components Model for Analysis of Covariance in Designed Experiments

2009 ◽  
Vol 24 (2) ◽  
pp. 223-237 ◽  
Author(s):  
James G. Booth ◽  
Walter T. Federer ◽  
Martin T. Wells ◽  
Russell D. Wolfinger
Keyword(s):  
Variance Components ◽  
Analysis Of Covariance ◽  
Designed Experiments

Analysis of Covariance

2021 ◽  
pp. 161-176
Author(s):  
Andy Hector
Keyword(s):  
Experimental Study ◽  
Linear Regression ◽  
Detailed Analysis ◽  
Explanatory Variable ◽  
Atmospheric Pollutants ◽  
Analysis Of Covariance ◽  
Designed Experiments ◽  
Low Level ◽  
Agricultural Yields

ANCOVA of designed experiments combines one categorical and one continuous explanatory variable. Panel plots are usually the best way to graphically display ANCOVA designs, with a separate linear regression within each level of the factor. ANCOVA can test for effects of both variables and interactions between them. The chapter focuses on ANCOVA of designed experiments. A detailed analysis is given of a subset of the variables from an experimental study of the effects of low-level atmospheric pollutants and drought on agricultural yields.

Effects of a 6-Week Straw Phonation in Water Exercise Program on the Aging Voice

2020 ◽  
Vol 63 (4) ◽  
pp. 1018-1032
Author(s):  
Chia-Hsin Wu ◽  
Roger W. Chan
Keyword(s):  
Acoustic Analysis ◽  
Vocal Tract ◽  
Exercise Program ◽  
Analysis Of Covariance ◽  
Elderly Subjects ◽  
Control Group ◽  
Perceptual Evaluation ◽  
Positive Effects ◽  
Aging Voice ◽  
Before And After

Purpose Semi-occluded vocal tract (SOVT) exercises with tubes or straws have been widely used for a variety of voice disorders. Yet, the effects of longer periods of SOVT exercises (lasting for weeks) on the aging voice are not well understood. This study investigated the effects of a 6-week straw phonation in water (SPW) exercise program. Method Thirty-seven elderly subjects with self-perceived voice problems were assigned into two groups: (a) SPW exercises with six weekly sessions and home practice (experimental group) and (b) vocal hygiene education (control group). Before and after intervention (2 weeks after the completion of the exercise program), acoustic analysis, auditory–perceptual evaluation, and self-assessment of vocal impairment were conducted. Results Analysis of covariance revealed significant differences between the two groups in smoothed cepstral peak prominence measures, harmonics-to-noise ratio, the auditory–perceptual parameter of breathiness, and Voice Handicap Index-10 scores postintervention. No significant differences between the two groups were found for other measures. Conclusions Our results supported the positive effects of SOVT exercises for the aging voice, with a 6-week SPW exercise program being a clinical option. Future studies should involve long-term follow-up and additional outcome measures to better understand the efficacy of SOVT exercises, particularly SPW exercises, for the aging voice.

Exploring Particular Facets of Cognitive Emotion Regulation and Their Relationships With Nonsuicidal Self-Injury Among Adolescents

Crisis ◽  
2019 ◽  
Vol 40 (4) ◽  
pp. 280-286 ◽  
Author(s):  
Nir Madjar ◽  
Nicole Segal ◽  
Gilad Eger ◽  
Gal Shoval
Keyword(s):  
Emotion Regulation ◽  
High School Students ◽  
Analysis Of Covariance ◽  
Depression Symptoms ◽  
Emotion Regulation Strategies ◽  
Cognitive Emotion Regulation ◽  
School Students ◽  
Self Injury ◽  
Regulation Strategies ◽  
Nonsuicidal Self Injury

Abstract. Background: Nonsuicidal self-injury (NSSI) has been found to be associated with poor emotion regulation. Aims: The goal of this study was to examine the association of multidimensional cognitive emotion regulation strategies with NSSI among adolescents and compare the different patterns of NSSI. Method: A sample of 594 high-school students (54.4% boys; mean age = 14.96 years), from five regional schools across Israel, were assessed for five facets of cognitive emotion regulation strategies (acceptance, refocus on planning, positive refocusing, putting into perspective, and positive reappraisal) and NSSI behaviors using validated scales. Participants were allocated into three groups: repetitive NSSI (more than six occasions of NSSI; 7.1%), occasional NSSI (at least one incident but less than six; 8.3%), and no NSSI (84.6%). Results: Analysis of covariance, controlling for gender and depression symptoms, revealed that students with NSSI reported higher levels of acceptance, but lower levels of refocus on planning and putting into perspective. Limitations: The study used a cross-sectional design, which was a limitation. Conclusion: These findings demonstrate that particular cognitive emotion regulation strategies differ substantially in their relationship with NSSI. Adolescents who focus on planning and putting stressful situations into perspective may have increased resilience, whereas adolescents who are accepting of negative events that have happened may be more prone to maladaptive coping behaviors.

Influence of General and Crystallized Intelligence on Vocabulary Test Performance

2002 ◽  
Vol 18 (1) ◽  
pp. 78-84 ◽  
Author(s):  
Eva Ullstadius ◽  
Jan-Eric Gustafsson ◽  
Berit Carlstedt
Keyword(s):  
Hierarchical Model ◽  
Test Performance ◽  
Verbal Ability ◽  
Testing Procedure ◽  
Intellectual Ability ◽  
Analysis Of Covariance ◽  
Categorical Variables ◽  
Vocabulary Test ◽  
Crystallized Intelligence ◽  
General Ability

Summary: Vocabulary tests, part of most test batteries of general intellectual ability, measure both verbal and general ability. Newly developed techniques for confirmatory factor analysis of dichotomous variables make it possible to analyze the influence of different abilities on the performance on each item. In the testing procedure of the Computerized Swedish Enlistment test battery, eight different subtests of a new vocabulary test were given randomly to subsamples of a representative sample of 18-year-old male conscripts (N = 9001). Three central dimensions of a hierarchical model of intellectual abilities, general (G), verbal (Gc'), and spatial ability (Gv') were estimated under different assumptions of the nature of the data. In addition to an ordinary analysis of covariance matrices, assuming linearity of relations, the item variables were treated as categorical variables in the Mplus program. All eight subtests fit the hierarchical model, and the items were found to load about equally on G and Gc'. The results also indicate that if nonlinearity is not taken into account, the G loadings for the easy items are underestimated. These items, moreover, appear to be better measures of G than the difficult ones. The practical utility of the outcome for item selection and the theoretical implications for the question of the origin of verbal ability are discussed.

The Effects of Age, Gene Source and Familial Severity on Factor VIII in Normals and Haemophilia Carriers: Analysis by Multiple Regression

1983 ◽  
Vol 50 (03) ◽  
pp. 722-725 ◽  
Author(s):  
Bruce M Duncan ◽  
Lynn J Tunbridge ◽  
John V Lloyd
Keyword(s):  
Factor Viii ◽  
Multiple Regression ◽  
Analysis Of Covariance ◽  
Severe Haemophilia ◽  
Factor Viii Related Antigen ◽  
Defective Gene ◽  
Coagulant Activity

SummaryThere are conflicting views on the effects of age, gene source and familial severity on levels of factor VIII in carriers of haemophilia. Different workers have found that factor VIII increases with age, is higher in paternal carriers, and is higher in carriers from families with more severe haemophilia. Other workers have disagreed with these findings. In this study we explored some of the causes of this conflict. We measured factor VIII related antigen and factor VIII coagulant activity on 40 normal females and 48 carriers, and analysed the results by multiple regression and analysis of covariance. Our results indicated that both factor VIII coagulant activity and factor VIII related antigen increased with age, but were unaffected by the familial severity of haemophilia or whether the defective gene came from the mother or the father. We found that the conflicting reports of previous authors were due to high inter-correlations of the studied variables.

The effectiveness of positive training on happiness, aggression and hope in adolescents with leukemia in Ahvaz

2018 ◽  
Vol 9 (01) ◽  
Author(s):  
Marzieh . Shamkhani ◽  
Ali . Khalafi
Keyword(s):  
Sampling Method ◽  
Analysis Of Covariance ◽  
Control Group ◽  
Positive Attitudes ◽  
Measurement Tools ◽  
Post Test ◽  
Aggression Questionnaire ◽  
Experimental Group ◽  
Period Measurement

The purpose of this study was to determine the effectiveness of positive learning on happiness, Aggression and hope for adolescents with leukemia in Ahvaz. The sample consisted of 30 people who were selected by available sampling method. 15 subjects in the experimental group and 15 in the control group were randomly assigned. The experimental design was a pre-test-post-test type with control group and follow-up period. Measurement tools included Oxford Happiness Inventory (Argyle, 1989); Ahwaz's Aggression Questionnaire (Zahedifar, Najarian, and Shokrkon, 2000); Hope Scale (Schneider, 1991). To run, at first, the pre-test was taken from both groups. Then, the experimental group was trained in 14 sessions of 90 minutes, and after each group, they were subjected to post-test. And one month later, the follow-up process was completed. Data analysis was performed using multivariate covariance analysis (MANCOVA) and one-way analysis of covariance (ANCOVA). The results showed that positive attitudes toward happiness, aggressiveness and hopefulness of adolescents with leukemia in Ahvaz were effective.

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