Introduction to Sample Size Choice for Confidence Intervals Based on t Statistics     

Xiaofeng Steven Liu  Brandon Loudermilk  Thomas Simpson 《Measurement in physical education and exercise science》2014,18(2):91-100

Sample size can be chosen to achieve a specified width in a confidence interval. The probability of obtaining a narrow width given that the confidence interval includes the population parameter is defined as the power of the confidence interval, a concept unfamiliar to many practitioners. This article shows how to utilize the Statistical Analysis System (SAS) proc power procedure to determine an appropriate sample size and achieve sufficient power for a specified confidence interval. Two examples in sport and exercise science are used to illustrate sample size determination for confidence intervals in the dependent and independent t tests. The relevant SAS code and output are provided with detailed annotations. As the use of confidence intervals becomes a more integral part of studies in sport and exercise science, the reporting and analysis of their power should be considered much like that of hypothesis tests.  相似文献   

Exploring athletic identity in elite-level English youth football: a cross-sectional approach     

Tom O. Mitchell  Mark Nesti  David Richardson  Adrian W. Midgley  Martin Eubank 《Journal of sports sciences》2014,32(13):1294-1299

Abstract

This study is the first empirical investigation that has explored levels of athletic identity in elite-level English professional football. The importance of understanding athletes’ psychological well-being within professional sport has been well documented. This is especially important within the professional football industry, given the high attrition rate (Anderson, G., & Miller, R. M. (2011). The academy system in English professional football: Business value or following the herd? University of Liverpool, Management School Research Paper Series. Retrieved from http://www.liv.ac.uk/managementschool/research/working%20papers/wp201143.pdf) and distinct occupational practices (Roderick, M. (2006). The work of professional football. A labour of love? London: Routledge). A total of 168 elite youth footballers from the English professional football leagues completed the Athletic Identity Measurement Scale (AIMS). Multilevel modelling was used to examine the effect of playing level, living arrangements and year of apprentice on the total AIMS score and its subscales (i.e., social identity, exclusivity and negative affectivity). Football club explained 30% of the variance in exclusivity among players (P = .022). Mean social identity was significantly higher for those players in the first year of their apprenticeship compared to the second year (P = .025). All other effects were not statistically significant (P > .05). The novel and unique findings have practical implications in the design and implementation of career support strategies with respect to social identity. This may facilitate the maintenance of motivation over a 2-year apprenticeship and positively impact on performance levels within the professional football environment.  相似文献   

Sport,Counterfactual History and Rugby's Twin Codes     

Adrian Smith 《国际体育史杂志》2013,30(1):97-108

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A Woman of substance     

Ronald D. Simpson 《Innovative Higher Education》1991,16(1):5-6

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The institute of information scientists criteria for information science     

I. S. Simpson 《Information processing & management》1977,13(6):385-387

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Single maximal versus combination punch kinematics     

Piorkowski BA  Lees A  Barton GJ 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(1):1-11

The aim of this study was to determine the influence of punch type (Jab, Cross, Lead Hook and Reverse Hook) and punch modality (Single maximal, 'In-synch' and 'Out of synch' combination) on punch speed and delivery time. Ten competition-standard volunteers performed punches with markers placed on their anatomical landmarks for 3D motion capture with an eight-camera optoelectronic system. Speed and duration between key moments were computed. There were significant differences in contact speed between punch types (F(2,18,84.87) = 105.76, p = 0.001) with Lead and Reverse Hooks developing greater speed than Jab and Cross. There were significant differences in contact speed between punch modalities (F(2,64,102.87) = 23.52, p = 0.001) with the Single maximal (M+/- SD: 9.26 +/- 2.09 m/s) higher than 'Out of synch' (7.49 +/- 2.32 m/s), 'In-synch' left (8.01 +/- 2.35 m/s) or right lead (7.97 +/- 2.53 m/s). Delivery times were significantly lower for Jab and Cross than Hook. Times were significantly lower 'In-synch' than a Single maximal or 'Out of synch' combination mode. It is concluded that a defender may have more evasion-time than previously reported. This research could be of use to performers and coaches when considering training preparations.  相似文献   

e-Trust and reputation     

Thomas W. Simpson 《Ethics and Information Technology》2011,13(1):29-38

Trust online can be a hazardous affair; many are trustworthy, but some people use the anonymity of the web to behave very badly indeed. So how can we improve the quality of evidence for trustworthiness provided online? I focus on one of the devices we use to secure others’ trustworthiness: tracking past conduct through online reputation systems. Yet existing reputation systems face problems. I analyse these, and in the light of this develop some principles for system design, towards overcoming these challenges. In providing better evidence for trustworthiness online, so we can also encourage people actually to be trustworthy more often, which is an ethically welcome outcome.  相似文献   

The effect of a supported exercise programme in patients with newly diagnosed Type 2 diabetes: a pilot study     

Backx K  McCann A  Wasley D  Dunseath G  Luzio S  Owens D 《Journal of sports sciences》2011,29(6):579-586

The aim of this study was to examine the effectiveness of either a standard care programme (n = 9) or a 12-week supported exercise programme (n = 10) on glycaemic control, β-cell responsiveness, insulin resistance, and lipid profiles in newly diagnosed Type 2 diabetes patients. The standard care programme consisted of advice to exercise at moderate to high intensity for 30 min five times a week; the supported exercise programme consisted of three 60-min supported plus two unsupported exercise sessions per week. Between-group analyses demonstrated a difference for changes in low-density lipoprotein cholesterol only (standard care programme 0.01 mmol · L(-1), supported exercise programme -0.6 mmol · L(-1); P = 0.04). Following the standard care programme, within-group analyses demonstrated a significant reduction in waist circumference, whereas following the supported exercise programme there were reductions in glycosylated haemoglobin (6.4 vs. 6.0%; P = 0.007), waist circumference (101.4 vs. 97.2 cm; P = 0.021), body mass (91.7 vs. 87.9 kg; P = 0.007), body mass index (30.0 vs. 28.7 kg · m(-2); P = 0.006), total cholesterol (5.3 vs. 4.6 mmol · L(-1); P = 0.046), low-density lipoprotein cholesterol (3.2 vs. 2.6 mmol · L(-1); P = 0.028), fasting β-cell responsiveness (11.5 × 10(-9) vs. 7.0 × 10(-9) pmol · kg(-1) · min(-1); P = 0.009), and insulin resistance (3.0 vs. 2.1; P = 0.049). The supported exercise programme improved glycaemic control through enhanced β-cell function associated with decreased insulin resistance and improved lipid profile. This research highlights the need for research into unsupported and supported exercise programmes to establish more comprehensive lifestyle advice for Type 2 diabetes patients.  相似文献   

Public libraries as reserves of cultural and digital capital: Addressing inequality through digitalization     

Adrian Leguina  Sabina Mihelj  John Downey 《Library & information science research》2021,43(3):101103

Public libraries are among key sites for the acquisition of cultural capital, and possibly one of the most potent means through which the state can address inequality. While digitalization of public libraries already attracted significant scholarly attention, the evidence of its contribution to the acquisition of cultural skills and knowledge and social mobility remains limited, as does the conceptual understanding of links between digitalization, cultural capital, and social stratification. This article draws on two disconnected bodies of research, the sociological analysis of cultural capital and stratification and research on digital divides. To bridge these two bodies of research, the interplay of cultural and digital capital in public libraries was investigated. The extensive dataset from the UK Taking Part Survey (2016–17) was analyzed using two-step cluster analysis and multinomial regression models to explore the contrasting profiles of contemporary library users. Results identify four distinct user groups: Traditional, Active, Family, and Tech Access, which possess different degrees of cultural and digital capital, have different demographic profiles, and benefit from digitalized libraries in different ways. If libraries are to fulfil their role in reducing social inequalities, it is important that they tailor their digital services to the specific characteristics of each user group. This approach also provides a useful template for exploring the interplay of digitalization and (in)equality in other cultural institutions.  相似文献   

Six degrees of separation: Australian metadata initiatives and their relationships with international standards     

Adrian Cunningham 《Archival Science》2001,1(3):271-283

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