Consistency in systematic sampling

In design-based stereology, fixed parameters (such as volume, surface area, curve length, feature number, connectivity) of a non-random geometrical object are estimated by intersecting the object with randomly located and oriented geometrical probes (e.g. test slabs, planes, lines, points). Estimation accuracy may in principle be increased by increasing the number of probes, which are usually laid in a systematic pattern. An important prerequisite to increase accuracy, however, is that the relevant estimators are unbiased and consistent. The purpose of this paper is therefore to give sufficient conditions for the unbiasedness and strong consistency of design-based stereological estimators obtained by systematic sampling. Relevant mechanisms to increase sample size, compatible with stereological practice, are considered.

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Consistency in systematic sampling for stereology

Advances in Applied Probability ◽

10.2307/1428037 ◽

1996 ◽

Vol 28 (2) ◽

pp. 329-330

Author(s):

X. Gual Arnau ◽

L. M. Cruz-Orive

Keyword(s):

Surface Area ◽

Strong Consistency ◽

Sufficient Conditions ◽

Estimation Accuracy ◽

Systematic Sampling ◽

Geometrical Object ◽

Important Prerequisite ◽

Curve Length ◽

Systematic Pattern

In design-based stereology, fixed parameters (such as volume, surface area, curve length, feature number, connectivity) of a non-random geometrical object are estimated by intersecting the object with randomly located and oriented geometrical probes (e.g. test slabs, planes, lines, points), [4], [5], [8], [11], [12]. Estimation accuracy may in principle be increased by increasing the number of probes, which are usually laid in a systematic pattern, [1], [2], [3], [7], [9], [10]. An important prerequisite to increase accuracy, however, is that the relevant estimators are unbiased and consistent. Our purpose is therefore to give sufficient conditions for the unbiasedness and strong consistency of design-based stereological estimators obtained by systematic sampling.

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Consistency in systematic sampling for stereology

Advances in Applied Probability ◽

10.1017/s0001867800048187 ◽

1996 ◽

Vol 28 (02) ◽

pp. 329-330

Author(s):

X. Gual Arnau ◽

L. M. Cruz-Orive

Keyword(s):

Surface Area ◽

Strong Consistency ◽

Sufficient Conditions ◽

Estimation Accuracy ◽

Systematic Sampling ◽

Geometrical Object ◽

Important Prerequisite ◽

Curve Length ◽

Systematic Pattern

In design-based stereology, fixed parameters (such as volume, surface area, curve length, feature number, connectivity) of a non-random geometrical object are estimated by intersecting the object with randomly located and oriented geometrical probes (e.g. test slabs, planes, lines, points), [4], [5], [8], [11], [12]. Estimation accuracy may in principle be increased by increasing the number of probes, which are usually laid in a systematic pattern, [1], [2], [3], [7], [9], [10]. An important prerequisite to increase accuracy, however, is that the relevant estimators are unbiased and consistent. Our purpose is therefore to give sufficient conditions for the unbiasedness and strong consistency of design-based stereological estimators obtained by systematic sampling.

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Willingness of Greek general population to get a COVID-19 vaccine

Global Health Research and Policy ◽

10.1186/s41256-021-00188-1 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Georgia Kourlaba ◽

Eleni Kourkouni ◽

Stefania Maistreli ◽

Christina-Grammatiki Tsopela ◽

Nafsika-Maria Molocha ◽

...

Keyword(s):

Public Health ◽

General Population ◽

Data Collection ◽

Sample Size ◽

Significant Proportion ◽

Control Measures ◽

Systematic Sampling ◽

Computer Assisted ◽

Public Health Officials ◽

To Receive

Abstract Background Epidemiological data indicate that a large part of population needs to be vaccinated to achieve herd immunity. Hence, it is of high importance for public health officials to know whether people are going to get vaccinated for COVID-19. The objective of the present study was to examine the willingness of adult residents in Greece to receive a COVID-19 vaccine. Methods A cross-sectional was survey conducted among the adult general population of Greece between April 28, 2020 to May 03, 2020 (last week of lockdown), using a mixed methodology for data collection: Computer Assisted Telephone Interviewing (CATI) and Computer Assisted web Interviewing (CAWI). Using a sample size calculator, the target sample size was found to be around 1000 respondents. To ensure a nationally representative sample of the urban/rural population according to the Greek census 2011, a proportionate stratified by region systematic sampling procedure was used to recruit particpants. Data collection was guided through a structured questionnaire. Regarding willingness to COVID-19 vaccination, participants were asked to answer the following question: “If there was a vaccine available for the novel coronavirus, would you do it?” Results Of 1004 respondents only 57.7% stated that they are going to get vaccinated for COVID-19. Respondents aged > 65 years old, those who either themselves or a member of their household belonged to a vulnerable group, those believing that the COVID-19 virus was not developed in laboratories by humans, those believing that coronavirus is far more contagious and lethal compared to the H1N1 virus, and those believing that next waves are coming were statistically significantly more likely to be willing to get a COVID-19 vaccine. Higher knowledge score regarding symptoms, transmission routes and prevention and control measures against COVID-19 was significantly associated with higher willingness of respondents to get vaccinated. Conclusion A significant proportion of individuals in the general population are unwilling to receive a COVID-19 vaccine, stressing the need for public health officials to take immediate awareness-raising measures.

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Power in High‐Dimensional Testing Problems

Econometrica ◽

10.3982/ecta15844 ◽

2019 ◽

Vol 87 (3) ◽

pp. 1055-1069 ◽

Cited By ~ 1

Author(s):

Anders Bredahl Kock ◽

David Preinerstorfer

Keyword(s):

Asymptotic Normality ◽

Sample Size ◽

Parameter Space ◽

Sufficient Conditions ◽

High Dimensional ◽

Local Asymptotic Normality ◽

Asymptotic Power ◽

Asymptotic Size ◽

Power Of Tests ◽

Power Enhancement

Fan, Liao, and Yao (2015) recently introduced a remarkable method for increasing the asymptotic power of tests in high‐dimensional testing problems. If applicable to a given test, their power enhancement principle leads to an improved test that has the same asymptotic size, has uniformly non‐inferior asymptotic power, and is consistent against a strictly broader range of alternatives than the initially given test. We study under which conditions this method can be applied and show the following: In asymptotic regimes where the dimensionality of the parameter space is fixed as sample size increases, there often exist tests that cannot be further improved with the power enhancement principle. However, when the dimensionality of the parameter space increases sufficiently slowly with sample size and a marginal local asymptotic normality (LAN) condition is satisfied, every test with asymptotic size smaller than 1 can be improved with the power enhancement principle. While the marginal LAN condition alone does not allow one to extend the latter statement to all rates at which the dimensionality increases with sample size, we give sufficient conditions under which this is the case.

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On sufficient conditions for the strong consistency of least-squares estimates

Statistics ◽

10.1080/02331888.2012.760096 ◽

2013 ◽

Vol 48 (3) ◽

pp. 657-667

Author(s):

João Lita da Silva

Keyword(s):

Least Squares ◽

Strong Consistency ◽

Sufficient Conditions ◽

Least Squares Estimates

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Generalized Markov branching trees

Advances in Applied Probability ◽

10.1017/apr.2016.81 ◽

2017 ◽

Vol 49 (1) ◽

pp. 108-133

Author(s):

Harry Crane

Keyword(s):

Sample Size ◽

Tree Species ◽

Gene Tree ◽

Sufficient Conditions ◽

Statistical Properties ◽

Branching Trees ◽

Necessary And Sufficient ◽

Branching Property ◽

Fragmentation Trees ◽

Family Of Distributions

Abstract Motivated by the gene tree/species tree problem from statistical phylogenetics, we extend the class of Markov branching trees to a parametric family of distributions on fragmentation trees that satisfies a generalized Markov branching property. The main theorems establish important statistical properties of this model, specifically necessary and sufficient conditions under which a family of trees can be constructed consistently as sample size grows. We also consider the question of attaching random edge lengths to these trees.

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Systematic Sampling for Estimating Harvest-Induced Changes of a Forest Stand

Science and Humanities Journal ◽

10.47773/shj.1998.091.4 ◽

2009 ◽

Vol 9 (1) ◽

pp. 39-55

Author(s):

Dennis Peque ◽

Keyword(s):

Sample Size ◽

Standard Error ◽

Basal Area ◽

Systematic Sampling ◽

Relative Standard Error ◽

Stem Density ◽

Relative Standard ◽

The Individual ◽

Induced Changes ◽

Forest District

This study was conducted in Compartment 2012a in Bosinghausen Forest District in Germany covering an area of 5 hectared. Twenty two sampling plots were laid out in the field following systematic sampling design. Results showed that all estimates for all variables (e.g. tree heights, DBH, stem density, basal area and volume) under trees that were marked for cutting have higher relative standard error. This was due to higher dispersion of individual estimates in each plot. On the other hand, the simulation study shows that sampling efficiency can be acheived by increasing the sample size. When more samples are included, the relative standard error becomes low. From this study, it can be concluded that the variability of the estimates were affected by sample size and the variability of individual units in the population or the individual esitmates (in this case, estimates in each plot).

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FIBRIN-TYPE FIBRINOID IN HUMAN PLACENTA: A STEREOLOGICAL ANALYSIS OF ITS ASSOCIATION WITH INTERVILLOUS VOLUME AND VILLOUS SURFACE AREA

Image Analysis & Stereology ◽

10.5566/ias.v20.p1-7 ◽

2011 ◽

Vol 20 (1) ◽

pp. 1 ◽

Cited By ~ 2

Author(s):

Terry M Mayhew

Keyword(s):

Surface Area ◽

Test Point ◽

Systematic Sampling ◽

Vascular Perfusion ◽

Correlation And Regression Analysis ◽

Intervillous Space ◽

Terminal Villi ◽

Villous Surface ◽

Normal Gestation

Stereological methods were used to examine fibrin-type fibrinoid deposition in the intervillous spaces of human placentas collected during gestation (12-41 weeks) and from term pregnancies at low (400 m) and high (3.6 km) altitude. The main aim was to test predictions about the relationships between fibrinoid deposits and either the volume of intervillous space or the surface area of (intermediate + terminal) villi. Fields of view on Masson trichrome-stained paraffin sections were selected as part of a systematic sampling design which randomised section location and orientation. Relative and absolute volumes were estimated by test point counting and surfaces by intersection counting. Apparent differences were tested by analyses of variance and relationships by correlation and regression analysis. Fibrinoid volume increased during gestation and correlated positively with intervillous volume and villous surface area. However, relative to intervillous volume, the main increase in fibrinoid occurred towards term (36-41 weeks). At high altitude, placentas contained more intervillous space but less fibrinoid. At both altitudes, there were significant correlations between fibrinoid volume and villous surface area. In all cases, changes in fibrinoid volume were commensurate with changes in villous surface area. Whilst findings lend support to the notion that fibrinoid deposition during normal gestation is influenced by the quality of vascular perfusion, they also emphasise that the extent of the villous surface is a more generally important factor. The villous surface may influence the steady state between coagulation and fibrinolysis since some pro-coagulatory events operate at the trophoblastic epithelium. They occur notably at sites of trophoblast de-epithelialisation and these arise following trauma or during the extrusion phase of normal epithelial turnover.

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Adherence towards COVID-19 prevention measures and associated factors in Hossana town, South Ethiopia, 2021

10.22541/au.161951700.09150664/v1 ◽

2021 ◽

Author(s):

Temesgen Fonkamo ◽

LONSAKO WOILORO

Keyword(s):

Marital Status ◽

Sample Size ◽

Family Size ◽

Preventive Measures ◽

Well Being ◽

Developing Nations ◽

Systematic Sampling ◽

Prevention Measures ◽

Cross Sectional ◽

Advanced Analysis

Introduction: The covid-19 disease is a pandemic threat for humanity’s healthcare system, social, economic, and psychological well-being for both developed and developing nations. In the case of developing nations such as the resource of Ethiopia, however, the key obstacle is to buy the vaccine and administer it to their people.. In the study area, however, the degree of adherence to the covid-19 preventive measure was not well established. The aim of this study is to determine adherence to covid-19 prevention measures in Hossana town. Methods: From 3 to 29 January 2021, a community-based cross-sectional study was conducted among individuals living in the Hosanna town. We used a sample size of 384. The sample size was distributed to all 8 kebeles in proportion to the size of the households contained in each kebele in the town of Hossana. Systematic sampling methods were used and both descriptive and advanced analysis, data was entered into Epi-data and exported to SPSS. Binary logistic regression was used to identify variables associated with adherence to preventive measures for covid-19. Result: 50.4% of the study participants had good adherence with the COVID-19 preventive measures. 145 (38.5%) of all respondents had poor knowledge on COVID-19 preventive measures and 40.3 % had poor COVID-19 transmission methods knowledge. Age [AOR: 0.34; 95 % CI (0.131-0.912)], educational status [AOR: 0.32; 95% CI (0.165-0.632)], marital status [AOR: 2; % CI (1.191-3.803)], family size [AOR: 2.4; % CI (1.322-4.366)]] and covid-19 complication [AOR: 0.49: 95% CI (0.242-0.979)]] were significantly associated with covid-19 prevention measurement adherence in multivariate analysis. Conclusion: This study found that approximately half of the participants had poor adherence to COVID-19 preventive measures. Factors associated with covid-19 preventive measures were age, educational age, marital status, family size, and heard about complication of COVID-19 were associated with preventive measures.

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