Search results for "Sample size determination"

Systematic review of guidelines for internal validity in the design, conduct and analysis of preclinical biomedical experiments involving laboratory …

2020

Over the last two decades, awareness of the negative repercussions of flaws in the planning, conduct and reporting of preclinical research involving experimental animals has been growing. Several initiatives have set out to increase transparency and internal validity of preclinical studies, mostly publishing expert consensus and experience. While many of the points raised in these various guidelines are identical or similar, they differ in detail and rigour. Most of them focus on reporting, only few of them cover the planning and conduct of studies. The aim of this systematic review is to identify existing experimental design, conduct, analysis and reporting guidelines relating to preclinic…

2019

Abstract This paper examines the relationship between health endowment and later-life outcomes in the labour market. The analysis is based on reduced-form models in which labour market outcomes are regressed on genetic variants related to the increased risk of cardiovascular diseases. We use linked Finnish data that have many strengths. Genetic risk scores constitute exogenous measures for health endowment, and accurate administrative tax records on earnings, employment and social income transfers provide a comprehensive account of an individual’s long-term performance in the labour market. The results show that although the direction of an effect is generally consistent with theoretical re…

Sample size in the monitoring of benthic macrofauna in the profundal of lakes: evaluation of the precision of estimates

1996

We discuss here the influence of sample size (number of replicates) on the accuracy and precision of the results when sampling profundal benthos with an Ekman grab according to the Finnish standard, SFS 5076, which is equivalent to the Swedish and Norwegian standards. The aim was to find criteria for choosing a sample size which would avoid any powerful influence of chance on the results without entailing an unreasonable amount of work for monitoring purposes.

Caries prevalence in children from Valencia (Spain) using ICDAS II criteria, 2010

2014

Objectives: To assess the oral health status of the child population and its evolution over the 2004-2010 period. Study Design: A descriptive cross-sectional study of the entire schoolchild population of the Valencia region of Spain was conducted using cluster sampling. Seventy schools were selected. The sample size was 1373 pupils, aged 6, 12 and 15 years. The children were examined in November and December 2010, at their schools, by 6 examiners calibrated in the ICDAS II method. The descriptive statistics, comparison of means and comparison of proportions (p0) was 30% in primary dentition at 6 years and 37.7% and 43.6% in permanent dentition at 12 and 15 years respectively. At 6, 12 and 1…

Relation between diagnosis of atheromatous plaque from orthopantomographs and cardiovascular risk factors. A study of cases and control subjects.

2014

Background In recent years the use of orthopantomography has been proposed as a low-cost, reliable and non-invasive diagnostic medium for detecting atheromatous plaque. The purpose of this study was to correlate the presence of carotid calcifications (atheroma) in orthopantomographs with specific risk factors for cerebrovascular accidents (previous cerebrovascular accidents, arterial hypertension, and diabetes). Material and Methods The methods used in this observational study of cases and control subjects followed STROBE (Strengthening the Reporting of Observational studies in Epidemiology) recommendations. The study analyzed a total of 1,602 panoramic radiographs taken for dental diagnost…

Three Issues in Multilevel Research

2019

AbstractIn this article, three important issues in organizational multilevel research are discussed and clarified, namely: (a) The interpretation of “cross-level direct effects” in theoretical and research multilevel models, (b) the specification of the emergence processes involved in higher-level constructs, and (c) the sample size recommendations for using multilevel statistical methods. By doing so, this article hopes to contribute to the improvement of organizational multilevel research.

Somatic symptoms in the Eastern and Western states of Germany 30 years after unification: Population-based survey analyses.

2021

Background Following German reunification, physical health indicators in the formerly separated states (German Democratic Republic- East/ Federal Republic of Germany-West) have converged. However, it remains unclear how these societal changes have impacted somatic complaints, a major indicator of physical and mental health. Therefore, we investigated how somatic symptom reporting in men and women evolved regarding residency. Methods We administered cross-sectional surveys representative of the German population with comparable sample size in 1994 (N = 3047), 2001 (N = 2050), 2013 (N = 2508) and 2019 (N = 2531) following random route procedure. Men and women aged 14-99 reported demographics …

The moderating effects of vigilance on other components of attentional functioning.

2018

Abstract Background Previous research suggested that vigilance may moderate the functioning of other attentional components. However, vigilance is usually neglected when comparing the attentional functioning between groups of clinical and/or healthy participants. New method We combined data from several studies using the Attention Network Test for Interactions and Vigilance (ANTI-V), which includes a vigilance measure plus phasic alertness, orienting, and executive control scores. We estimated, for the first time, the reliability of the vigilance performance indices in the ANTI-V, by analyzing split-half correlations of 10,000 permutations of the trials. In addition, we tested whether a dif…

Testing an emotion regulation model of physical activity in adolescents with anorexia nervosa: A pilot ecological momentary assessment.

2019

Objective Adolescents with anorexia nervosa (AN) often show increased levels of exercise and physical activity. Psychological models suggest that physical activity in AN might attenuate momentary negative affect. However, this has not been directly tested in adolescents with AN, and it remains unclear whether this is a distinct mechanism of physical activity in AN compared with healthy controls (HCs). Method In a 1-day ecological momentary assessment, 32 adolescent inpatients with AN and 30 HCs responded to hourly questions on momentary affect while wearing an actigraph to objectively assess physical activity. Results Linear mixed models identified that adolescents with AN experienced more …

Analgesics use in competitive triathletes: its relationship to doping and on predicting its usage

2016

The two major objectives of this study were (i) to assess variables that predict the use of analgesics in competitive athletes and (ii) to test whether the use of analgesics is associated with the use of doping. A questionnaire primarily addressing the use of analgesics and doping was distributed among 2,997 triathletes. Binary logistic regression analysis was performed to predict the use of analgesics. Moreover, the randomised response technique (RRT) was used to estimate the prevalence of doping in order to assess whether users of analgesics have a higher potential risk for doping than non-users. Statistical power analyses were performed to determine sample size. The bootstrap method was …