Statistical Inference, Learning and Models in Big Data
Total Page:16
File Type:pdf, Size:1020Kb
Load more
										Recommended publications
									
								- 
												  DATA COLLECTION METHODS Section III 5AN OVERVIEW OF QUANTITATIVE AND QUALITATIVE DATA COLLECTION METHODS Section III 5. DATA COLLECTION METHODS: SOME TIPS AND COMPARISONS In the previous chapter, we identified two broad types of evaluation methodologies: quantitative and qualitative. In this section, we talk more about the debate over the relative virtues of these approaches and discuss some of the advantages and disadvantages of different types of instruments. In such a debate, two types of issues are considered: theoretical and practical. Theoretical Issues Most often these center on one of three topics: · The value of the types of data · The relative scientific rigor of the data · Basic, underlying philosophies of evaluation Value of the Data Quantitative and qualitative techniques provide a tradeoff between breadth and depth, and between generalizability and targeting to specific (sometimes very limited) populations. For example, a quantitative data collection methodology such as a sample survey of high school students who participated in a special science enrichment program can yield representative and broadly generalizable information about the proportion of participants who plan to major in science when they get to college and how this proportion differs by gender. But at best, the survey can elicit only a few, often superficial reasons for this gender difference. On the other hand, separate focus groups (a qualitative technique related to a group interview) conducted with small groups of men and women students will provide many more clues about gender differences in the choice of science majors, and the extent to which the special science program changed or reinforced attitudes. The focus group technique is, however, limited in the extent to which findings apply beyond the specific individuals included in the groups.
- 
												  Data Extraction for Complex Meta-Analysis (Decimal) GuidePedder, H. , Sarri, G., Keeney, E., Nunes, V., & Dias, S. (2016). Data extraction for complex meta-analysis (DECiMAL) guide. Systematic Reviews, 5, [212]. https://doi.org/10.1186/s13643-016-0368-4 Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.1186/s13643-016-0368-4 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via BioMed Central at http://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-016-0368-4. Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ Pedder et al. Systematic Reviews (2016) 5:212 DOI 10.1186/s13643-016-0368-4 RESEARCH Open Access Data extraction for complex meta-analysis (DECiMAL) guide Hugo Pedder1*, Grammati Sarri2, Edna Keeney3, Vanessa Nunes1 and Sofia Dias3 Abstract As more complex meta-analytical techniques such as network and multivariate meta-analyses become increasingly common, further pressures are placed on reviewers to extract data in a systematic and consistent manner. Failing to do this appropriately wastes time, resources and jeopardises accuracy. This guide (data extraction for complex meta-analysis (DECiMAL)) suggests a number of points to consider when collecting data, primarily aimed at systematic reviewers preparing data for meta-analysis.
- 
												  Minimum Sample Sizes for On-Road Measurements of CarView metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by International Institute for Applied Systems Analysis (IIASA) Manuscript – Final and authoritative paper published in Environmental Science & Technology, 18 Oct 2019. https://pubs.acs.org/doi/abs/10.1021/acs.est.9b04123 1 When is enough? Minimum sample sizes for on-road 2 measurements of car emissions 3 Yuche Chen‡ *, Yunteng Zhang‡, Jens Borken-Kleefeld† * 4 ‡Department of Civil and Environmental Engineering, University of South Carolina, USA 5 †International Institute for Applied System Analysis, Laxenburg, Austria 6 * Corresponding author: Yuche Chen, [email protected]; Jens Borken-Kleefeld, 7 [email protected] 8 9 Key words: Monte Carlo simulation, bootstrap, in-use surveillance, diesel car, Europe, Euro 6, 10 mean, variance, remote emission sensing. 11 Manuscript – Final and authoritative paper published in Environmental Science & Technology, 18 Oct 2019. https://pubs.acs.org/doi/abs/10.1021/acs.est.9b04123 12 ABSTRACT 13 The power of remote vehicle emission sensing stems from the big sample size obtained and its 14 related statistical representativeness for the measured emission rates. But how many records are 15 needed for a representative measurement and when does the information gain per record become 16 insignificant? We use Monte Carlo simulations to determine the relationship between the sample 17 size and the accuracy of the sample mean and variance. We take the example of NO emissions 18 from diesel cars measured by remote emission monitors between 2011 and 2018 at various 19 locations in Europe. We find that no more than 200 remote sensing records are sufficient to 20 approximate the mean emission rate for Euro 4, 5 and 6a,b diesel cars with 80% certainty within 21 a ±1 g NO per kg fuel tolerance margin (~±50 mg NO per km).
- 
												  Likelihood-Based Random-Effects Meta-Analysis with Few StudiesSeide et al. RESEARCH Likelihood-based random-effects meta-analysis with few studies: Empirical and simulation studies Svenja E Seide1,2†, Christian R¨over1* and Tim Friede1ˆ Abstract Background: Standard random-effects meta-analysis methods perform poorly when applied to few studies only. Such settings however are commonly encountered in practice. It is unclear, whether or to what extent small-sample-size behaviour can be improved by more sophisticated modeling. Methods: We consider likelihood-based methods, the DerSimonian-Laird approach, Empirical Bayes, several adjustment methods and a fully Bayesian approach. Confidence intervals are based on a normal approximation, or on adjustments based on the Student-t-distribution. In addition, a linear mixed model and two generalized linear mixed models (GLMMs) assuming binomial or Poisson distributed numbers of events per study arm are considered for pairwise binary meta-analyses. We extract an empirical data set of 40 meta-analyses from recent reviews published by the German Institute for Quality and Efficiency in Health Care (IQWiG). Methods are then compared empirically and as well as in a simulation study, based on few studies, imbalanced study sizes, and considering odds-ratio (OR) and risk ratio (RR) effect sizes. Coverage probabilities and interval widths for the combined effect estimate are evaluated to compare the different approaches. Results: Empirically, a majority of the identified meta-analyses include only 2 studies. Variation of methods or effect measures affects the estimation results. In the simulation study, coverage probability is, in the presence of heterogeneity and few studies, mostly below the nominal level for all frequentist methods based on normal approximation, in particular when sizes in meta-analyses are not balanced, but improve when confidence intervals are adjusted.
- 
												  Targeted Maximum Likelihood Estimation of Treatment Effects InTargeted maximum likelihood estimation of treatment e®ects in randomized controlled trials and drug safety analysis by Kelly L. Moore A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Biostatistics in the GRADUATE DIVISION of the UNIVERSITY OF CALIFORNIA, BERKELEY Committee in charge: Professor Mark J. van der Laan, Chair Professor Ira B. Tager Professor Alan E. Hubbard Fall 2009 The dissertation of Kelly L. Moore, titled Targeted maximum likelihood estimation of treatment e®ects in randomized controlled trials and drug safety analysis, is approved: Chair Date Date Date University of California, Berkeley Fall 2009 Targeted maximum likelihood estimation of treatment e®ects in randomized controlled trials and drug safety analysis Copyright 2009 by Kelly L. Moore 1 Abstract Targeted maximum likelihood estimation of treatment e®ects in randomized controlled trials and drug safety analysis by Kelly L. Moore Doctor of Philosophy in Biostatistics University of California, Berkeley Professor Mark J. van der Laan, Chair In most randomized controlled trials (RCTs), investigators typically rely on estimators of causal e®ects that do not exploit the information in the many baseline covariates that are routinely collected in addition to treatment and the outcome. Ignoring these covariates can lead to a signi¯cant loss is estimation e±ciency and thus power. Statisticians have underscored the gain in e±ciency that can be achieved from covariate adjustment in RCTs with a focus on problems involving linear models. Despite recent theoretical advances, there has been a reluctance to adjust for covariates based on two primary reasons; 1) covariate-adjusted estimates based on non-linear regression models have been shown to be less precise than unadjusted methods, and, 2) concern over the opportunity to manipulate the model selection process for covariate adjustment in order to obtain favorable results.
- 
												  Reasoning with Qualitative Data: Using Retroduction with Transcript DataReasoning With Qualitative Data: Using Retroduction With Transcript Data © 2019 SAGE Publications, Ltd. All Rights Reserved. This PDF has been generated from SAGE Research Methods Datasets. SAGE SAGE Research Methods Datasets Part 2019 SAGE Publications, Ltd. All Rights Reserved. 2 Reasoning With Qualitative Data: Using Retroduction With Transcript Data Student Guide Introduction This example illustrates how different forms of reasoning can be used to analyse a given set of qualitative data. In this case, I look at transcripts from semi-structured interviews to illustrate how three common approaches to reasoning can be used. The first type (deductive approaches) applies pre-existing analytical concepts to data, the second type (inductive reasoning) draws analytical concepts from the data, and the third type (retroductive reasoning) uses the data to develop new concepts and understandings about the issues. The data source – a set of recorded interviews of teachers and students from the field of Higher Education – was collated by Dr. Christian Beighton as part of a research project designed to inform teacher educators about pedagogies of academic writing. Interview Transcripts Interviews, and their transcripts, are arguably the most common data collection tool used in qualitative research. This is because, while they have many drawbacks, they offer many advantages. Relatively easy to plan and prepare, interviews can be flexible: They are usually one-to one but do not have to be so; they can follow pre-arranged questions, but again this is not essential; and unlike more impersonal ways of collecting data (e.g., surveys or observation), they Page 2 of 13 Reasoning With Qualitative Data: Using Retroduction With Transcript Data SAGE SAGE Research Methods Datasets Part 2019 SAGE Publications, Ltd.
- 
												  Model-Based Estimation Official StatisticsModel-Basedd Estimationmatio for Offi cial SStatistics08007atistics Jan van den Brakel and Jelke Bethlehem The views expressed in this paper are those of the author(s) and do not necessarily refl ect the policies of Statistics Netherlands Discussionpaper (08002) Statistics Netherlands Voorburg/Heerlen, 2008 Explanation of symbols . = data not available * = provisional fi gure x = publication prohibited (confi dential fi gure) – = nil or less than half of unit concerned – = (between two fi gures) inclusive 0 (0,0) = less than half of unit concerned blank = not applicable 2005-2006 = 2005 to 2006 inclusive 2005/2006 = average of 2005 up to and including 2006 2005/’06 = crop year, fi nancial year, school year etc. beginning in 2005 and ending in 2006 2003/’04–2005/’06 = crop year, fi nancial year, etc. 2003/’04 to 2005/’06 inclusive Due to rounding, some totals may not correspond with the sum of the separate fi gures. Publisher Statistics Netherlands second half of 2008: Prinses Beatrixlaan 428 Henri Faasdreef 312 2273 XZ Voorburg 2492 JP The Hague Prepress Statistics Netherlands - Facility Services Cover TelDesign, Rotterdam Information Telephone .. +31 88 570 70 70 Telefax .. +31 70 337 59 94 Via contact form: www.cbs.nl/information Where to order E-mail: [email protected] Telefax .. +31 45 570 62 68 Internet http://www.cbs.nl ISSN: 1572-0314 © Statistics Netherlands, Voorburg/Heerlen, 2008. 6008308002 X-10 Reproduction is permitted. ‘Statistics Netherlands’ must be quoted as source. Summary: This paper summarizes the advantages and disadvantages of design-based and model-assisted estimation procedures that are widely applied by most of the European national statistical institutes.
- 
												  Chapter 5 Statistical InferenceChapter 5 Statistical Inference CHAPTER OUTLINE Section 1 Why Do We Need Statistics? Section 2 Inference Using a Probability Model Section 3 Statistical Models Section 4 Data Collection Section 5 Some Basic Inferences In this chapter, we begin our discussion of statistical inference. Probability theory is primarily concerned with calculating various quantities associated with a probability model. This requires that we know what the correct probability model is. In applica- tions, this is often not the case, and the best we can say is that the correct probability measure to use is in a set of possible probability measures. We refer to this collection as the statistical model. So, in a sense, our uncertainty has increased; not only do we have the uncertainty associated with an outcome or response as described by a probability measure, but now we are also uncertain about what the probability measure is. Statistical inference is concerned with making statements or inferences about char- acteristics of the true underlying probability measure. Of course, these inferences must be based on some kind of information; the statistical model makes up part of it. Another important part of the information will be given by an observed outcome or response, which we refer to as the data. Inferences then take the form of various statements about the true underlying probability measure from which the data were obtained. These take a variety of forms, which we refer to as types of inferences. The role of this chapter is to introduce the basic concepts and ideas of statistical inference. The most prominent approaches to inference are discussed in Chapters 6, 7, and 8.
- 
												  Invasive Plant Researchers Should Calculate Effect Sizes, Not P-Values Author(S): Matthew JInvasive Plant Researchers Should Calculate Effect Sizes, Not P-Values Author(s): Matthew J. Rinella and Jeremy J. James Source: Invasive Plant Science and Management, 3(2):106-112. 2010. Published By: Weed Science Society of America DOI: 10.1614/IPSM-09-038.1 URL: http://www.bioone.org/doi/full/10.1614/IPSM-09-038.1 BioOne (www.bioone.org) is an electronic aggregator of bioscience research content, and the online home to over 160 journals and books published by not-for-profit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Invasive Plant Science and Management 2010 3:106–112 Review Invasive Plant Researchers Should Calculate Effect Sizes, Not P-Values Matthew J. Rinella and Jeremy J. James* Null hypothesis significance testing (NHST) forms the backbone of statistical inference in invasive plant science. Over 95% of research articles in Invasive Plant Science and Management report NHST results such as P-values or statistics closely related to P-values such as least significant differences. Unfortunately, NHST results are less informative than their ubiquity implies.
- 
												  Background MaterialAppendix A Background Material All who debate on matters of uncertainity, should be free from prejudice, partiality, anger, or compassion. —Caius Sallustius Crispus A.1 Some Classical Likelihood Theory Most of the VGLM/VGAM framework is infrastructure directed towards maxi- mizing a full-likelihood model, therefore it is useful to summarize some supporting results from classical likelihood theory. The following is a short summary of a few selected topics serving the purposes of this book. The focus is on aspects of di- rect relevance to the practitioners and users of the software. The presentation is informal and nonrigorous; rigorous treatments, including justification and proofs, can be found in the texts listed in the bibliographic notes. The foundation of this subject was developed by Fisher a century ago (around the decade of WW1), and he is regarded today as the father of modern statistics. A.1.1 Likelihood Functions The usual starting point is to let Y be a random variable with density func- T tion f(y; θ) depending on θ =(θ1,...,θp) , a multidimensional unknown param- eter. Values that Y can take are denoted in lower-case, i.e., y. By ‘density function’, here is meant a probability (mass) function for a discrete-valued Y , and probabil- ity density function for continuous Y . We shall refer to f as simply the density function, and use integration rather than summation to denote quantities such as expected values, e.g., E(Y )= f(y) dy where the range of integration is over the support of the distribution, i.e., those values of y where f(y) > 0 (called Y).
- 
												  Data Collection, Data Quality and the History of Cause-Of-Death Classifi CationChapter 8 Data Collection, Data Quality and the History of Cause-of-Death Classifi cation Vladimir Shkolnikov , France Meslé , and Jacques Vallin Until 1996, when INED published its work on trends in causes of death in Russia (Meslé et al . 1996 ) , there had been no overall study of cause-specifi c mortality for the Soviet Union as a whole or for any of its constituent republics. Yet at least since the 1920s, all the republics had had a modern system for registering causes of death, and the information gathered had been subject to routine statistical use at least since the 1950s. The fi rst reason for the gap in the literature was of course that, before perestroika, these data were not published systematically and, from 1974, had even been kept secret. A second reason was probably that researchers were often ques- tioning the data quality; however, no serious study has ever proved this. On the contrary, it seems to us that all these data offer a very rich resource for anyone attempting to track and understand cause-specifi c mortality trends in the countries of the former USSR – in our case, in Ukraine. Even so, a great deal of effort was required to trace, collect and computerize the various archived data deposits. This chapter will start with a brief description of the registration system and a quick summary of the diffi culties we encountered and the data collection methods we used. We shall then review the results of some studies that enabled us to assess the quality of the data.
- 
												  INTRODUCTION, HISTORY SUBJECT and TASK of STATISTICS, CENTRAL STATISTICAL OFFICE ¢ SZTE Mezőgazdasági Kar, Hódmezővásárhely, Andrássy Út 15STATISTISTATISTICSCS INTRODUCTION, HISTORY SUBJECT AND TASK OF STATISTICS, CENTRAL STATISTICAL OFFICE SZTE Mezőgazdasági Kar, Hódmezővásárhely, Andrássy út 15. GPS coordinates (according to GOOGLE map): 46.414908, 20.323209 AimAim ofof thethe subjectsubject Name of the subject: Statistics Curriculum codes: EMA15121 lect , EMA151211 pract Weekly hours (lecture/seminar): (2 x 45’ lectures + 2 x 45’ seminars) / week Semester closing requirements: Lecture: exam (2 written); seminar: 2 written Credit: Lecture: 2; seminar: 1 Suggested semester : 2nd semester Pre-study requirements: − Fields of training: For foreign students Objective: Students learn and utilize basic statistical techniques in their engineering work. The course is designed to acquaint students with the basic knowledge of the rules of probability theory and statistical calculations. The course helps students to be able to apply them in practice. The areas to be acquired: data collection, information compressing, comparison, time series analysis and correlation study, reviewing the overall statistical services, land use, crop production, production statistics, price statistics and the current system of structural business statistics. Suggested literature: Abonyiné Palotás, J., 1999: Általános statisztika alkalmazása a társadalmi- gazdasági földrajzban. Use of general statistics in socio-economic geography.) JATEPress, Szeged, 123 p. Szűcs, I., 2002: Alkalmazott Statisztika. (Applied statistics.) Agroinform Kiadó, Budapest, 551 p. Reiczigel J., Harnos, A., Solymosi, N., 2007: Biostatisztika nem statisztikusoknak. (Biostatistics for non-statisticians.) Pars Kft. Nagykovácsi Rappai, G., 2001: Üzleti statisztika Excellel. (Business statistics with excel.) KSH Hunyadi, L., Vita L., 2008: Statisztika I. (Statistics I.) Aula Kiadó, Budapest, 348 p. Hunyadi, L., Vita, L., 2008: Statisztika II. (Statistics II.) Aula Kiadó, Budapest, 300 p. Hunyadi, L., Vita, L., 2008: Statisztikai képletek és táblázatok (oktatási segédlet).