scholarly journals An efficient modification to diagonal systematic sampling for finite populations

2021 ◽  
Vol 6 (5) ◽  
pp. 5193-5204
Author(s):  
Muhammad Azeem ◽  
◽  
Muhammad Asif ◽  
Muhammad Ilyas ◽  
Muhammad Rafiq ◽  
...  
Keyword(s):  
Systematic Sampling ◽  
Finite Populations

scholarly journals Estimation under Balanced Systematic Sampling for Parabolic Populations

2006 ◽  
Vol 5 (1) ◽  
pp. 65-74
Author(s):  
S. Sampath ◽  
M. A. Basker
Keyword(s):  
Finite Population ◽  
Population Models ◽  
Systematic Sampling ◽  
Finite Populations ◽  
Population Total

Construction of estimators of finite population total for populations exhibiting known trend has attracted the attention of many researchers. In this paper, two estimators for total of finite populations exhibiting parabolic trend are proposed under balanced systematic sampling and their performances have ben assessed with the help of appropriate super population models.

scholarly journals Perinatal Asphyxia Among Neonates Admitted Jimma Medical Center, Jimma, Ethiopia

2020 ◽  
Vol 7 ◽  
pp. 2333794X2098130
Author(s):  
Ebissa Bayana Kebede ◽  
Adugna Olani Akuma ◽  
Yonas Biratu Tarfa
Keyword(s):  
Gestational Age ◽  
Medical Center ◽  
Perinatal Asphyxia ◽  
Mode Of Delivery ◽  
Large For Gestational Age ◽  
Systematic Sampling ◽  
P Value ◽  
Health Extension Workers ◽  
Severe Problem ◽  
Prolonged Labor

Background: Perinatal asphyxia is a severe problem which causes serious problem in neonates in developing countries. This study is aimed to determine magnitude of perinatal asphyxia and its associated factors. Methods: A cross-sectional study design was conducted among neonates admitted over a period of 4 years on 740 samples. Systematic sampling method was employed to get required samples from log book. Epi-data 3.1 is used for data entry and the entered data was exported to SPSS Version 23 for analysis. Bivariable and multiple variable logistic regressions analysis were applied to see the association between dependent and independent variables. Finally, P-value <.05 at 95% CI was declared statistically significant. Results: The main significant factor associated to perinatal asphyxia were prolonged labor ( P = .04, AOR = 1.68 95%CI: [1.00, 2.80]), being primipara ( P = .003, AOR = 2.06, 95%CI: [1.28, 3.30]), Small for Gestational Age (SGA) ( P = .001, AOR = 4.35, 95%CI: [1.85, 10.19]), Large for Gestational Age ( P = .001, AOR = 16.75, 95%CI: [3.82, 73.33]) and mode of delivery. Conclusion: The magnitude of perinatal asphyxia was 18%. Prolonged labor, parity, birth size, mode of delivery, and APGAR score at 1st minute were significantly associated with perinatal asphyxia. So, Nurses, Midwives, Medical Doctors, and health extension workers have to engage and contribute to on how to decrease the magnitude of perinatal asphyxia.

scholarly journals Recombination Can Evolve in Large Finite Populations Given Selection on Sufficient Loci

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2249-2258 ◽  
Author(s):  
Mark M Iles ◽  
Kevin Walters ◽  
Chris Cannings
Keyword(s):  
Experimental Evidence ◽  
Genetic Drift ◽  
Finite Population ◽  
Selective Advantage ◽  
Indirect Selection ◽  
Small Populations ◽  
Finite Populations ◽  
Population Sizes ◽  
Population Recombination

AbstractIt is well known that an allele causing increased recombination is expected to proliferate as a result of genetic drift in a finite population undergoing selection, without requiring other mechanisms. This is supported by recent simulations apparently demonstrating that, in small populations, drift is more important than epistasis in increasing recombination, with this effect disappearing in larger finite populations. However, recent experimental evidence finds a greater advantage for recombination in larger populations. These results are reconciled by demonstrating through simulation without epistasis that for m loci recombination has an appreciable selective advantage over a range of population sizes (am, bm). bm increases steadily with m while am remains fairly static. Thus, however large the finite population, if selection acts on sufficiently many loci, an allele that increases recombination is selected for. We show that as selection acts on our finite population, recombination increases the variance in expected log fitness, causing indirect selection on a recombination-modifying locus. This effect is enhanced in those populations with more loci because the variance in phenotypic fitnesses in relation to the possible range will be smaller. Thus fixation of a particular haplotype is less likely to occur, increasing the advantage of recombination.

scholarly journals Comparison of Variance Estimators for Systematic Environmental Sample Surveys: Considerations for Post-Stratified Estimation

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 772
Author(s):  
Bryce Frank ◽  
Vicente J. Monleon
Keyword(s):  
Random Sampling ◽  
Simple Random Sampling ◽  
National Forest Inventory ◽  
Point Estimation ◽  
Systematic Sampling ◽  
Sampling Variance ◽  
Variance Estimators ◽  
The Past ◽  
Point Estimators ◽  
Species Specific

The estimation of the sampling variance of point estimators under two-dimensional systematic sampling designs remains a challenge, and several alternative variance estimators have been proposed in the past few decades. In this work, we compared six alternative variance estimators under Horvitz-Thompson (HT) and post-stratification (PS) point estimation regimes. We subsampled a multitude of species-specific forest attributes from a large, spatially balanced national forest inventory to compare the variance estimators. A variance estimator that assumes a simple random sampling design exhibited positive relative bias under both HT and PS point estimation regimes ranging between 1.23 to 1.88 and 1.11 to 1.78 for HT and PS, respectively. Alternative estimators reduced this positive bias with relative biases ranging between 1.01 to 1.66 and 0.90 to 1.64 for HT and PS, respectively. The alternative estimators generally obtained improved efficiencies under both HT and PS, with relative efficiency values ranging between 0.68 to 1.28 and 0.68 to 1.39, respectively. We identified two estimators as promising alternatives that provide clear improvements over the simple random sampling estimator for a wide variety of attributes and under HT and PS estimation regimes.

Log-Linear Models with Dependent Spatial Data

1983 ◽  
Vol 15 (6) ◽  
pp. 801-813 ◽  
Author(s):  
B Fingleton
Keyword(s):  
Spatial Data ◽  
Statistical Models ◽  
Linear Models ◽  
Square Lattice ◽  
Categorical Variables ◽  
Systematic Sampling ◽  
Pairwise Correlations ◽  
Independent Observations ◽  
Intersection Points ◽  
Log Linear

Log-linear models are an appropriate means of determining the magnitude and direction of interactions between categorical variables that in common with other statistical models assume independent observations. Spatial data are often dependent rather than independent and thus the analysis of spatial data by log-linear models may erroneously detect interactions between variables that are spurious and are the consequence of pairwise correlations between observations. A procedure is described in this paper to accommodate these effects that requires only very minimal assumptions about the nature of the autocorrelation process given systematic sampling at intersection points on a square lattice.

Query Size Estimation for Joins Using Systematic Sampling

2004 ◽  
Vol 15 (3) ◽  
pp. 237-275 ◽  
Author(s):  
A.H.H. Ngu ◽  
B. Harangsri ◽  
J. Shepherd
Keyword(s):  
Systematic Sampling ◽  
Size Estimation ◽  
Query Size Estimation
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