Senatorial signatures

2021 ◽  
pp. 1-7
Author(s):  
Nancy L. Segal ◽  
Francisca J. Niculae
Keyword(s):  
Statistical Power ◽  
Genetic Factors ◽  
Small Sample Size ◽  
Small Sample ◽  
Contributing Factors ◽  
Left Handedness ◽  
Left Handed ◽  
Males And Females ◽  
General Populations ◽  
Larger Sample

Abstract A greater frequency of left-handedness among males than females has been observed in general populations. Past studies have explained this difference with reference to males’ greater susceptibility to adverse birth events, while more recent studies have identified other contributing factors. On January 16, 2020, U.S. senators signed an oath to act impartially during the president’s impeachment trial. This televised event allowed direct comparison of the proportion of right-handedness and left-handedness in a professionally accomplished sample of males and females. As expected, no sex difference in the proportion of left-handed senators was found, although the small sample size offered low statistical power. Replicating this finding with a larger sample would support the view that left-handedness among select groups of males is linked to genetic factors.

Statistical Power Analysis can Improve Fisheries Research and Management

1990 ◽  
Vol 47 (1) ◽  
pp. 2-15 ◽  
Author(s):  
Randall M. Peterman
Keyword(s):  
Sample Size ◽  
Power Analysis ◽  
Statistical Power ◽  
Small Sample Size ◽  
Industrial Effluent ◽  
Small Sample ◽  
Detectable Effect ◽  
Type Ii ◽  
Sampling Variability ◽  
Statistical Power Analysis

Ninety-eight percent of recently surveyed papers in fisheries and aquatic sciences that did not reject some null hypothesis (H0) failed to report β, the probability of making a type II error (not rejecting H0 when it should have been), or statistical power (1 – β). However, 52% of those papers drew conclusions as if H0 were true. A false H0 could have been missed because of a low-power experiment, caused by small sample size or large sampling variability. Costs of type II errors can be large (for example, for cases that fail to detect harmful effects of some industrial effluent or a significant effect of fishing on stock depletion). Past statistical power analyses show that abundance estimation techniques usually have high β and that only large effects are detectable. I review relationships among β, power, detectable effect size, sample size, and sampling variability. I show how statistical power analysis can help interpret past results and improve designs of future experiments, impact assessments, and management regulations. I make recommendations for researchers and decision makers, including routine application of power analysis, more cautious management, and reversal of the burden of proof to put it on industry, not management agencies.

Nipple Confusion

PEDIATRICS ◽  
1993 ◽  
Vol 92 (2) ◽  
pp. 300-301
Author(s):  
DOREN FREDRICKSON
Keyword(s):  
Breast Feeding ◽  
Statistical Power ◽  
White Women ◽  
Small Sample Size ◽  
False Negative ◽  
Small Sample ◽  
Bottle Feeding ◽  
Feeding Duration ◽  
Breast Feed ◽  
The Impact

To the Editor.— I wish to comment on the study reported by Cronenwett et al,1 which was a fascinating prospective study among married white women who planned to breast-feed. Women were randomly selected to perform either exdusive breast-feeding or partial breast-feeding with bottled human milk supplements to determine the impact of infant temperament and limited bottle-feeding on breast-feeding duration. The authors admit that small sample size and lack of statistical power make a false-negative possible.

scholarly journals Aetiological factors in left-handedness

2005 ◽  
Vol 133 (11-12) ◽  
pp. 532-534 ◽  
Author(s):  
Sanja Milenkovic ◽  
Goran Belojevic ◽  
Radojka Kocijancic
Keyword(s):  
Genetic Factors ◽  
The Body ◽  
Intrauterine Environment ◽  
Foetal Development ◽  
Ultrasound Exposure ◽  
The Past ◽  
Left Handedness ◽  
Left Handed ◽  
Efferent Pathways ◽  
Genetically Determined

Lateralisation associates the extremities and senses of one side of the body, which are connected by afferent and efferent pathways, with the primary motor and sensory areas of the hemisphere on the opposite side. Dominant laterality denotes the appearance of a dominant extremity or sense in the performance of complex psychomotor activities. Laterality is manifested both as right-handedness or left-handedness, which are functionally equivalent and symmetrical in the performance of activities. Right-handedness is significantly more common than left-handedness. Genetic theory is most widely accepted in explaining the onset of lateralisation. According to this theory, the models of brain organisation asymmetry (anatomical, functional, and biochemical) are strongly, genetically determined. However, the inability to clearly demonstrate the association between genetic factors and left-handedness has led researchers to investigate the effects of the environment on left-handedness. Of particular interest are the intrauterine environment and the factors influencing foetal development, of which hormones and ultrasound exposure are the most significant. It has been estimated that an extra five cases of nonright-handed lateralisation can be expected in every 100 males who were exposed to ultrasound in utero compared to those who were not. Socio-cultural pressure on left-handed individuals was much more severe in the past, which is confirmed by scientific findings that left-handedness is present in 13% of individuals in their twenties, while in less than 1% of individuals in their eighties.

scholarly journals The incidence of left-handedness: a meta-analysis [1993]

2019 ◽  
Author(s):  
Ian Christopher McManus
Keyword(s):  
Sex Difference ◽  
Meta Analysis ◽  
Birth Cohorts ◽  
Future Studies ◽  
Left Handedness ◽  
Left Handed ◽  
Method Of Measurement ◽  
Males And Females ◽  
Older Subjects ◽  
Unpublished Manuscripts

A meta-analysis is reported of 88 studies, examining 100 study populations, in which the handedness of 284665 individuals has been assessed. The overall incidence of left-handedness was 7.78%. The incidence of left-handedness was not related to the method of measurement, or the length or number of response items included in inventories. Study populations with lower response rates and smaller study populations showed some evidence of higher incidences of left-handedness, presumably due to response biasses. There was no evidence that the incidence of left-handedness was related to the year of publication of studies; however the incidence of left-handedness was lower in older subjects and in those from earlier birth cohorts, the two effects not being statistically distinguishable.Information was available from 64 study populations concerning the incidence of left-handedness in males and females; overall 8.52% of males were left-handed compared with 6.69% of females, the male incidence being 27.4% higher than that in females. Although there was some suggestion that the sex difference was greater in larger studies, and in studies whose main purpose was not the study of handedness, these differences were not significant. It is concluded that the size of the sex difference is unrelated to any of the moderator variables we have studied.It was not possible to carry out a meta-analysis of degree of handedness due to wide-spread differences in the method of reporting of degree of handedness.We recommend that future studies of handedness should, as a minimum, use one of three standard methods of assessment, so that comparison of studies is facilitated. Note: This manuscript was originally prepared in 1993 but due to problems at a major journal, described briefly, was never eventually published. It has however been cited on a number of occasions, and has been available at https://www.ucl.ac.uk/medical-education/publications/unpublished-manuscripts/meta-analysis-of-handedness . A major meta-analysis of handedness in 2019 by another author has now been submitted which cites this manuscript, and therefore it needs to be available in a more archivable format.

scholarly journals Chloroquine and Hydroxychloroquine could be an Available Weapons to Treat COVID-19 Associated Pneumonia

2020 ◽  
pp. 52-60
Author(s):  
Nehad J. Ahmed
Keyword(s):  
Clinical Trials ◽  
Angiotensin Converting Enzyme ◽  
Sample Size ◽  
Small Sample Size ◽  
Small Sample ◽  
Google Scholar ◽  
Converting Enzyme ◽  
Larger Sample

Aims: This study aims to review the efficacy of chloroquine and hydroxychloroquine to treat coronavirus disease 2019 (COVID-19) associated pneumonia. Methodology: This review includes searching Google scholar for publications about the use of hydroxychloroquinein the treatment of COVID-19 using the words of (Covid-19) AND hydroxychloroquine. Results: Chloroquine and hydroxychloroquine have proven effective in treating coronavirus in China in vitro, but till now only few clinical trials are available and these trials were conducted on a small sample size of the patients. The efficacy of chloroquine and hydroxychloroquine is mainly due to its effect on angiotensin-converting enzyme II (ACE2). Conclusion: The use of chloroquine and hydroxychloroquine could be very promising but more trials are needed that include larger sample size and more data are required about the comparison between chloroquine and hydroxychloroquine with other antivirals.

scholarly journals Prevalence and Heritability of Handedness in a Hong Kong Chinese Twin and Singleton Sample

2019 ◽  
Author(s):  
Mo Zheng ◽  
Catherine McBride ◽  
Connie Suk-Han Ho ◽  
Jonathan Ka-Chun Chan ◽  
Kwong Wai Choy ◽  
...  
Keyword(s):  
Hong Kong ◽  
Genetic Factors ◽  
Reference Data ◽  
Hand Preference ◽  
Hong Kong Chinese ◽  
Left Handedness ◽  
Left Handed ◽  
Chinese School ◽  
Heritability Analysis ◽  
Definition Of

Left-Handedness prevalence has been consistently reported at around 10% with heritability estimates at around 25%. Higher left-handedness prevalence has been reported in males and in twins. Lower prevalence has been reported in Asia, but it remains unclear whether this is due to biological or cultural factors. Most studies are based on samples with European ethnicities and using the preferred hand for writing as the key assessment. Here, we investigated handedness in a sample of Chinese school children in Hong Kong, including 426 singletons and 205 pairs of twins, using both the Edinburgh Handedness Inventory and Pegboard Task. Based on a binary definition of writing hand, we found a higher prevalence of left-handedness (8%) than what was previously reported in Asian datasets. We found no evidence of increased left-handedness in twins, but our results were in line with previous findings showing that males have a higher tendency to be left-handed than females. Heritability was similar for both hand preference (21%) and laterality indexes (22%). However, these two handedness measures present only a moderate correlation (.42) and appear to be underpinned by different genetic factors. In summary, we report new reference data for an ethnic group usually underrepresented in the literature. Our heritability analysis supports the idea that different measures will capture different components of handedness and, as a consequence, datasets assessed with heterogeneous criteria are not easily combined or compared.

scholarly journals Comparison of statistical methods for analysis of small sample sizes for detecting the differences in efficacy between treatments for knee osteoarthritis

2020 ◽  
Author(s):  
Chia-Lung Shih ◽  
Te-Yu Hung
Keyword(s):  
Knee Osteoarthritis ◽  
Sample Size ◽  
Statistical Methods ◽  
Statistical Power ◽  
Permutation Test ◽  
Small Sample Size ◽  
Small Sample ◽  
T Test ◽  
Sample Sizes ◽  
Knee Oa

Abstract Background A small sample size (n < 30 for each treatment group) is usually enrolled to investigate the differences in efficacy between treatments for knee osteoarthritis (OA). The objective of this study was to use simulation for comparing the power of four statistical methods for analysis of small sample size for detecting the differences in efficacy between two treatments for knee OA. Methods A total of 10,000 replicates of 5 sample sizes (n=10, 15, 20, 25, and 30 for each group) were generated based on the previous reported measures of treatment efficacy. Four statistical methods were used to compare the differences in efficacy between treatments, including the two-sample t-test (t-test), the Mann-Whitney U-test (M-W test), the Kolmogorov-Smirnov test (K-S test), and the permutation test (perm-test). Results The bias of simulated parameter means showed a decreased trend with sample size but the CV% of simulated parameter means varied with sample sizes for all parameters. For the largest sample size (n=30), the CV% could achieve a small level (<20%) for almost all parameters but the bias could not. Among the non-parametric tests for analysis of small sample size, the perm-test had the highest statistical power, and its false positive rate was not affected by sample size. However, the power of the perm-test could not achieve a high value (80%) even using the largest sample size (n=30). Conclusion The perm-test is suggested for analysis of small sample size to compare the differences in efficacy between two treatments for knee OA.

Abstract W P20: A Model to Calculate the Expected Treatment Effect in Acute Endovascular Stroke Trials

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Maarten G Lansberg ◽  
Robin Lemmens ◽  
Soren Christensen ◽  
Nishant K Mishra ◽  
Gregory W Albers
Keyword(s):  
Literature Review ◽  
Sample Size ◽  
Endovascular Therapy ◽  
Treatment Effect ◽  
Small Sample Size ◽  
Small Sample ◽  
Absolute Difference ◽  
Sample Size Calculations ◽  
And Control ◽  
Larger Sample

Background: Recent trials have shown no benefit of endovascular therapy. This may, in part, be explained by inaccurate estimates of the treatment effect used in the sample size calculations of these trials. A predictive model which includes variables that modify the expected treatment effect might yield more accurate estimates, and could be valuable in the design of future acute stroke trials. Methods: We conducted a literature review to obtain estimates of parameters that are associated with good functional outcome (GFO) following recanalization. We developed a model to estimate the treatment effect in endovascular stroke trials and applied this model to two recently published endovascular stroke trials. Results: We estimated a 40% absolute difference in the proportion of GFO (mRS 0-2 at 90 days) associated with reperfusion in patients with ICA or M1 occlusions who have a substantial ischemic penumbra at baseline. To estimate the effect size in trials, this value was multiplied by: 1) the proportion of patients undergoing endovascular therapy in the active treatment arm; 2) the proportion of patients with occlusions of the ICA or MCA-M1; 3) the proportion of patients with a substantial penumbra and a DWI lesion <50mL; and 4) the absolute difference in the proportion of patients with reperfusion, defined as TICI 2B-3, between the endovascular treatment and control arms. Based on literature review we assumed a reperfusion rate of 20% in the control arms of IMS III and MR Rescue, a 50% prevalence of patients with substantial penumbra and DWI lesions<50 mL in IMS III, and a 75% prevalence in the penumbral arms of MR Rescue. Based on these model inputs, a 2.2% increase in GFO with endovascular therapy was expected in IMS III, which closely matches the observed 2.1% increase. For MR Rescue, the model predicted a 1.5% increase in GFO with endovascular therapy. Considering the small sample size, this equates to 0.5 additional patients with GFO which closely matches the observed result of 3 fewer patients with GFO. Conclusion: A simple model shows promise for estimating the treatment effect of endovascular stroke trials. It may be useful for the design of future trials and could lead to different inclusion criteria or larger sample sizes compared to the recently conducted studies.

Three-year results of phase I retinal gene therapy trial for CNGA3-mutated achromatopsia: results of a non randomised controlled trial

2021 ◽  
pp. bjophthalmol-2021-319067
Author(s):  
Felix Friedrich Reichel ◽  
Stylianos Michalakis ◽  
Barbara Wilhelm ◽  
Ditta Zobor ◽  
Regine Muehlfriedel ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Primary Endpoint ◽  
Statistical Power ◽  
Small Sample Size ◽  
Controlled Trial ◽  
Statistical Significance ◽  
Small Sample ◽  
Functional Improvement ◽  
Limiting Factor ◽  
Serious Adverse Events

AimsTo determine long-term safety and efficacy outcomes of a subretinal gene therapy for CNGA3-associated achromatopsia. We present data from an open-label, nonrandomised controlled trial (NCT02610582).MethodsDetails of the study design have been previously described. Briefly, nine patients were treated in three escalating dose groups with subretinal AAV8.CNGA3 gene therapy between November 2015 and October 2016. After the first year, patients were seen on a yearly basis. Safety assessment constituted the primary endpoint. On a secondary level, multiple functional tests were carried out to determine efficacy of the therapy.ResultsNo adverse or serious adverse events deemed related to the study drug occurred after year 1. Safety of the therapy, as the primary endpoint of this trial, can, therefore, be confirmed. The functional benefits that were noted in the treated eye at year 1 were persistent throughout the following visits at years 2 and 3. While functional improvement in the treated eye reached statistical significance for some secondary endpoints, for most endpoints, this was not the case when the treated eye was compared with the untreated fellow eye.ConclusionThe results demonstrate a very good safety profile of the therapy even at the highest dose administered. The small sample size limits the statistical power of efficacy analyses. However, trial results inform on the most promising design and endpoints for future clinical trials. Such trials have to determine whether treatment of younger patients results in greater functional gains by avoiding amblyopia as a potential limiting factor.

Essential tremor: genetic update

2019 ◽  
Vol 21 ◽  
Author(s):  
Hao Deng ◽  
Shan Wu ◽  
Joseph Jankovic
Keyword(s):  
Essential Tremor ◽  
Animal Studies ◽  
Genetic Factors ◽  
Small Sample Size ◽  
Small Sample ◽  
Lower Limbs ◽  
Body Parts ◽  
Genetic Analyses ◽  
Disease Definition ◽  
Neurological Movement Disorder

Abstract Essential tremor (ET) is a neurological movement disorder characterised by bilateral limb kinetic/postural tremor, with or without tremor in other body parts including head, voice and lower limbs. Since no causative genes for ET have been identified, it is likely that the disorder occurs as a result of complex genetic factors interacting with various cellular and environmental factors that can result in abnormal function of circuitry involving the cerebello–thalamo–cortical pathway. Genetic analyses have uncovered at least 14 loci and 11 genes that are related to ET, as well as various risk or protective genetic factors. Limitations in ET genetic analyses include inconsistent disease definition, small sample size, varied ethnic backgrounds and many other factors that may contribute to paucity of relevant genetic data in ET. Genetic analyses, coupled with functional and animal studies, have led to better insights into possible pathogenic mechanisms underlying ET. These genetic studies may guide the future development of genetic testing and counselling, and specific, pathogenesis-targeted, therapeutic strategies.

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