An Experiment in Combining Estimates of Uncertainty

1990 ◽  
pp. 403-412
Author(s):  
Bruce Tonn ◽  
Richard Goeltz
Keyword(s):  
Combining Estimates

Note on Combining Estimates in Bioassay

1966 ◽  
Vol 8 (1-2) ◽  
pp. 7-9 ◽  
Author(s):  
B. M. Bennett
Keyword(s):  
Combining Estimates

scholarly journals Fundamental uncertainty levels of 21 cm power spectra from a delay analysis

2019 ◽  
Vol 487 (4) ◽  
pp. 5840-5853 ◽  
Author(s):  
Adam E Lanman ◽  
Jonathan C Pober
Keyword(s):  
Power Spectrum ◽  
Power Spectra ◽  
Low Frequency ◽  
Sample Variance ◽  
Model Parameters ◽  
Delay Analysis ◽  
Analysis Strategies ◽  
Murchison Widefield Array ◽  
Fundamental Uncertainty ◽  
Combining Estimates

Abstract Several experimental efforts are underway to measure the power spectrum of 21 cm fluctuations from the epoch of reionization (EoR) using low-frequency radio interferometers. Experiments like the Hydrogen Epoch of Reionization Array (HERA) and Murchison Widefield Array Phase II (MWA) feature highly redundant antenna layouts, building sensitivity through redundant measurements of the same angular Fourier modes, at the expense of diminished UV coverage. This strategy limits the numbers of independent samples of each power spectrum mode, thereby increasing the effect of sample variance on the final power spectrum uncertainty. To better quantify this effect, we measure the sample variance of a delay-transform based power spectrum estimator, using both analytic calculations and simulations of flat-spectrum EoR-like signals. We find that for the shortest baselines in HERA, the sample variance can reach as high as 20 per cent, and up to 30 per cent for the wider fields of view of the MWA. Combining estimates from all the baselines in a HERA- or MWA-like 37 element redundant hexagonal array can lower the variance to 1−3 per cent for some Fourier modes. These results have important implications for observing and analysis strategies, and suggest that sample variance can be non-negligible when constraining EoR model parameters from upcoming 21 cm data.

Combining Inventory Data for Improved Estimates of Forest Resources

1987 ◽  
Vol 11 (3) ◽  
pp. 168-171 ◽  
Author(s):  
Charles E. Thomas ◽  
John C. Rennie
Keyword(s):  
Basal Area ◽  
Forest Resources ◽  
Statistical Techniques ◽  
Inventory Data ◽  
Sampling Errors ◽  
Wayne County ◽  
Sampling Problems ◽  
To Receive ◽  
Combining Estimates ◽  
Quantities Of Interest

Abstract Foresters occasionally have two or more estimates of the same volume, basal area, or other quantities of interest from independent inventories. A variety of statistical techniques for combining such estimates recently have begun to receive attention in surveys of census characteristics,agriculture, and forestry. Results from two independent timber resource inventories in Wayne County, Tennessee, are reported along with their respective sampling errors. Methods for combining estimates along with example calculations are presented and discussed. Suggestions are made for theapplication of this procedure to other sampling problems. South. J. Appl. For. 11(3):168-171.

scholarly journals Multiple Imputation of Missing Values: New Features for Mim

2009 ◽  
Vol 9 (2) ◽  
pp. 252-264 ◽  
Author(s):  
Patrick Royston ◽  
John B. Carlin ◽  
Ian R. White
Keyword(s):  
Monte Carlo ◽  
Multiple Imputation ◽  
Missing Values ◽  
Parameter Estimates ◽  
Sampling Variability ◽  
Combining Estimates ◽  
Multiply Imputed

We present an update of mim, a program for managing multiply imputed datasets and performing inference (estimating parameters) using Rubin's rules for combining estimates from imputed datasets. The new features of particular importance are an option for estimating the Monte Carlo error (due to the sampling variability of the imputation process) in parameter estimates and in related quantities, and a general routine for combining any scalar estimate across imputations.

Understanding Australia’s national feral cat control effort

2020 ◽  
Vol 47 (8) ◽  
pp. 698
Author(s):  
Georgia E. Garrard ◽  
Alexander M. Kusmanoff ◽  
Richard Faulkner ◽  
Chathuri L. Samarasekara ◽  
Ascelin Gordon ◽  
...  
Keyword(s):  
Threatened Species ◽  
Native Species ◽  
Control Effort ◽  
Data Repositories ◽  
Feral Cat ◽  
Feral Cats ◽  
Mixed Methods Approach ◽  
Qualitative Responses ◽  
The Impact ◽  
Combining Estimates

Abstract Context. Feral cats (Felis catus) pose a significant threat to Australia’s native species and feral cat control is, therefore, an important component of threatened species management and policy. Australia’s Threatened Species Strategy articulates defined targets for feral cat control. Yet, currently, little is known about who is engaged in feral cat control in Australia, what motivates them, and at what rate they are removing feral cats from the environment. Aims. We aim to document who is engaging in feral cat control in Australia, how many cats they remove and to estimate the number of feral cats killed in a single year. Furthermore, we seek to better understand attitudes towards feral cat control in Australia. Methods. We used a mixed methods approach combining quantitative and qualitative techniques. Feral cat control data were obtained from existing data repositories and via surveys targeting relevant organisations and individuals. A bounded national estimate of the number of feral cats killed was produced by combining estimates obtained from data repositories and surveys with modelled predictions for key audience segments. Attitudes towards feral cat control were assessed by exploring qualitative responses to relevant survey questions. Key results. We received information on feral cat control from three central repositories, 134 organisations and 2618 individuals, together removing more than 35000 feral cats per year. When including projections to national populations of key groups, the estimated number of feral cats removed from the environment in the 2017–2018 financial year was 316030 (95% CI: 297742–334318). Conclusions. Individuals and organisations make a significant, and largely unrecorded, contribution to feral cat control. Among individuals, there is a strong awareness of the impact of feral cats on Australia’s biodiversity. Opposition to feral cat control focussed largely on ethical concerns and doubts about its efficacy. Implications. There is significant interest in, and commitment to, feral cat control among some groups of Australian society, beyond the traditional conservation community. Yet more information is needed about control methods and their effectiveness to better understand how these efforts are linked to threatened species outcomes.

scholarly journals Combining Estimates of Tectonic Plate Rotations:

1998 ◽  
Vol 65 (1) ◽  
pp. 71-108 ◽  
Author(s):  
Bessie H. Kirkwood ◽  
Ted Chang
Keyword(s):  
Tectonic Plate ◽  
Combining Estimates

scholarly journals Rates of microfilarial production by Onchocerca volvulus are not cumulatively reduced by multiple ivermectin treatments

Parasitology ◽  
2008 ◽  
Vol 135 (13) ◽  
pp. 1571-1581 ◽  
Author(s):  
CHRISTIAN BOTTOMLEY ◽  
VALERIE ISHAM ◽  
RICHARD C. COLLINS ◽  
MARIA-GLORIA BASÁÑEZ
Keyword(s):  
Death Rate ◽  
Female Worm ◽  
Cumulative Effect ◽  
Onchocerca Volvulus ◽  
Treatment Level ◽  
Treatment Programme ◽  
Fertility Effect ◽  
Drug Treatments ◽  
Pre Treatment ◽  
Combining Estimates

SUMMARYRegular distribution of ivermectin reduces onchocerciasis transmission and morbidity by killing, within humans, the microfilarial stage of the parasite (microfilaricidal effect). In addition, ivermectin exerts a so-called embryostatic effect by which microfilarial production by the adult female worm becomes suppressed during a number of weeks after treatment. To assess the overall effect of ivermectin on onchocerciasis transmission and evaluate the likelihood of local elimination of the infection it is important to estimate the magnitude of the anti-fertility effect over the course of a treatment programme. Estimates of the effect of repeated drug treatments on the production of microfilariae by adult Onchocerca volvulus were obtained by developing a model that was fitted to data collected from three hyperendemic communities in Guatemala, where eligible residents received ivermectin twice per year for two and a half years. The data consist of microfilarial load measurements in the skin, collected just before each six-monthly treatment during the programme. The model that is developed describes the dynamics of an individual host's expected microfilarial load over the 30-month study period. We adopt a Bayesian approach and use Markov chain Monte Carlo (McMC) techniques to fit the model to the data. Combining estimates from the three villages, average microfilarial production in the first six months post-treatment was reduced by ~64% of its pre-treatment level, regardless of values chosen for the pre-ivermectin fertility rate within plausible ranges. Increased adult worm death rate after treatment (to mimic removal of macrofilariae via nodulectomy during the programme) resulted in a smaller estimated magnitude of the embryostatic effect (rate of microfilarial production was reduced by ~58% of pre-ivermectin value). After subsequent treatments, the rate of microfilarial production appeared to be similarly decreased. The data and analyses therefore do not support the hypothesis of a cumulative effect of multiple ivermectin treatments on microfilarial production by female worms.

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