scholarly journals How to draw the line in biomedical research

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Lisa Huang ◽  
Amir Rattner ◽  
Han Liu ◽  
Jeremy Nathans

The use of the least squares method to calculate the best-fitting line through a two-dimensional scatter plot typically requires the user to assume that one of the variables depends on the other. However, in many cases the relationship between the two variables is more complex, and it is not valid to say that one variable is independent and the other is dependent. When analysing such data researchers should consider plotting the three regression lines that can be calculated for any two-dimensional scatter plot.

1966 ◽  
Vol 29 (2) ◽  
pp. 49-52 ◽  
Author(s):  
R. Schneider ◽  
D. E. Jasper

Summary Variations in precision of the Breed method for cell counts in milk were investigated by utilizing different working factors (WF) for the same smear and by using the same WF over a major portion of the probable cell count range. A significant inverse relationship was found between precision and the WF. With a constant WF on the other hand, the precision of the count increased very significantly as the actual cell count increased. Formulas showing the relationship between the expected high and low for any given cell count were computed via the least squares method for a WF of 20,000. Evidence was presented that a WF of 5,000 or below would be necessary when a good estimate of cell content is important.


1958 ◽  
Vol 4 (6) ◽  
pp. 600-606 ◽  
Author(s):  
G. Power ◽  
P. Smith

A set of two-dimensional subsonic flows past certain cylinders is obtained using hodograph methods, in which the true pressure-volume relationship is replaced by various straight-line approximations. It is found that the approximation obtained by a least-squares method possibly gives best results. Comparison is made with values obtained by using the von Kármán-Tsien approximation and also with results obtained by the variational approach of Lush & Cherry (1956).


Author(s):  
Anar Eminov Et al.

According to the statistical data of recent years, tourism has been one of the ever-growing sectors in Azerbaijan. Thus, in the last five years, there has been a steady increase in the number of entrepreneurship subjects serving tourism in Azerbaijan and the number of foreign nationals traveling for tourism, correspondingly 4.5 and 8.5 percent. At present, the direct share of the tourism industry in the country's GDP and employment is 4.5 and 3.3 percent, respectively. In the article econometric analysis of the dependence on the relationship between tourism industry graduates and their development has been done. The regression equation of the dependence of the number of graduates studying tourism on the number of tourists in the country and the dependence of the tourism sector’s GDP on the number of graduates in the tourism sector were estimated using the Eviews software based on 2008–2017 statistical data using the least squares method.


2014 ◽  
Vol 10 (3) ◽  
pp. 314-337 ◽  
Author(s):  
Shakil Quayes ◽  
Tanweer Hasan

Purpose – The purpose of this paper is to analyze the relationship between financial disclosure and the financial performance of microfinance institutions (MFIs). Design/methodology/approach – The paper utilizes ordinary least squares method to analyze the impact of disclosure on financial performance, an ordered probit model to investigate the possible effect of financial performance on disclosure and utilizes a three-stage least squares method to delineate the endogenous relationship between disclosure and financial performance of MFIs. Findings – The paper finds that better disclosure has a statistically significant positive impact on operational performance of MFIs; second, it also shows that improved financial performance results in better financial disclosure. Keeping the endogenous nature of the relationship between disclosure and performance, the paper uses a three-stage least squares method to show that disclosure and financial performance positively affect each other simultaneously. Research limitations/implications – The paper attempts to delineate a positive association between better disclosure on financial performance of MFIs, which can be used for developing a better disclosure policy by management, formulating more effective guidelines for disclosure by the stakeholders and mandating more appropriate laws and uniform disclosure practice by regulators. Originality/value – This is the first study that uses a large number of MFIs from 75 countries; second, it uses a uniform scale of designating a disclosure rating (assigned by MIX Market) to show the relationship between disclosure and performance. Finally, it uses three-stage least squares method to address the possible endogeneity between disclosure and performance.


2021 ◽  
Author(s):  
José Israel Galindo-Rodríguez ◽  
Gilberto Silva-Ortigoza

Abstract The aim of the present work is to introduce a lens whose faces are a conical surface and a spherical surface. We illuminate this lens by a plane wavefront and its associated refracted wavefronts, light rays and caustic are computed. We find that the caustic region has two branches and can be virtual, real or one part virtual and the other real, depending on the values of the parameters characterizing the lens. Furthermore, we present a particular example where one of the branches of the caustic region is constituted by two segments of a line, one part is real and the other one virtual. The second branch is a two-dimensional surface with a singularity of the cusp ridge type such that its Gaussian curvature is different from zero. It is important to remark that for this example, the two branches of the caustic are disconnected. Because of this property and the result obtained by Berry and Balazs on the relationship between the acceleration of an Airy beam and the curvature of its corresponding caustic, we believe that using this optical element one could generate a scalar optical accelerating beam in the region where the caustic is a two-dimensional surface of revolution, and at the same time a scalar optical beam with similar properties to the Bessel beam of zero order in the region were the real caustic is a segment of a line along the optical axis.


Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1873
Author(s):  
Konrad Kułakowski

One of the most popular methods of calculating priorities based on the pairwise comparisons matrices (PCM) is the geometric mean method (GMM). It is equivalent to the logarithmic least squares method (LLSM), so some use both names interchangeably, treating it as the same approach. The main difference, however, is in the way the calculations are done. It turns out, however, that a similar relationship holds for incomplete matrices. Based on Harker’s method for the incomplete PCM, and using the same substitution for the missing entries, it is possible to construct the geometric mean solution for the incomplete PCM, which is fully compatible with the existing LLSM for the incomplete PCM. Again, both approaches lead to the same results, but the difference is how the final solution is computed. The aim of this work is to present in a concise form, the computational method behind the geometric mean method (GMM) for an incomplete PCM. The computational method is presented to emphasize the relationship between the original GMM and the proposed solution. Hence, everyone who knows the GMM for a complete PCM should easily understand its proposed extension. Theoretical considerations are accompanied by a numerical example, allowing the reader to follow the calculations step by step.


1981 ◽  
Vol 59 (18) ◽  
pp. 2746-2749 ◽  
Author(s):  
Chung Chieh ◽  
Sing Kwen Cheung

Ammonium dithiocarbamate, H2NCS2NH4, decomposes easily but the anion forms a stable mercury(II) complex, the crystals of which are orthorhombic with a = 7.851(3), b = 17.565(7), c = 12.051(3) Å, and space group Pbca. The structure was solved by the Patterson method and refined by the full-matrix least-squares method to an R of 0.038 for 781 reflections. The structure consists of layers of two-dimensional polymeric networks. The dimeric subunits in the layer containing two each of mutually connected Hg atoms and dithiocarbamates are further linked by other bridging dithiocarbamates forming a sheet-like structure. Each Hg atom bonds to four S atoms from four separate dithiocarbamates with Hg—S distances of 2.499(4), 2.508(4), 2.533(4), and 2.629(4) Å. The ir bands observed were: ν(NH2), 3320, 3220, 3125; δ(NH2), 1600; ν(C—N), 1395; ρr(NH2), 1172; and v(C—S), 840 cm−1. The mass spectrum of this polymeric compound gave peaks corresponding to Hg, S2, CNH2, HNCS, S, CS2, S5, S4, S3, and S8 in the order of their intensities.


2019 ◽  
Vol 20 (2) ◽  
pp. 83-92
Author(s):  
Małgorzata Kobylińska

This paper presents the application of the regression maximum depth for the estimation of linear regression function structural elements. For two-dimensional sets including untypical observations, regression functions were developed using the classical least squares method and a method based on the concept of observation depth measure in a sample. The effect of untypical observations on the estimated models has been noted.


2021 ◽  
Vol 4 (4) ◽  
Author(s):  
Ismail Karatas ◽  
◽  
Hayri Akyuz

This research was carried out to investigate of the relationship between the two-dimensional self-esteem perceptions and leadership orientations of the students of the faculty of sports sciences. In this context, the relational survey model, which is consistent with the main purpose of the study, was used in this quantitative study. A total of 323 students, 125 females and 198 males at the Faculty of Sports Sciences of Bartın University constitute the sample of the research. Convenience sampling method, one of the non-probabilistic sampling approaches, was used in the selection of the research group. Questionnaire form was used as data collection tool and this form consisted of three parts. The first part includes the “Personal Information Form,” the second part includes the “Two-Dimensional Self-Esteem: Self-Liking/Self-Competence Scale” and the third part includes the “Multidimensional Leadership Orientations Scale.” The descriptive statistics of the raw data obtained through the questionnaire form were first calculated by considering the data type. Then, the reliability of the scales related to the obtained data were investigated, and the difference and correlation tests were used in the statistical evaluation. In this direction, it has been determined that there are significant correlations within the scope of age and family income level variables. However, there was no significant relationship within the scope of personal income level variable. On the other hand, it was found that there are significant differences in the scope of department and actively doing sports variables. However, it was observed that there were no significant differences in the scope of gender, grade, and place of residence variables. On the other hand, it was determined that there were positive and moderately significant correlations between the participants’ scores of self-liking and political leadership, human resources leadership, charismatic leadership and structural leadership. In addition, it was found that there were positive and moderately significant correlations between the self-competence scores of the participants and the scores of political leadership, charismatic leadership and structural leadership. On the other hand, it was understood that there was a statistically significant positive and low-level correlation between the participants' self-competence scores and their human resources leadership scores. As a result, it can be said that as the self-esteem of the participants increases, their leadership orientation also increases. In this context, it can be said that increasing the self-esteem of the participants is an important concept in the context of leadership orientations.


Sign in / Sign up

Export Citation Format

Share Document