What is a survey?
Posted by Armando Brito Mendes | Filed under estatística, materiais ensino
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Alguns recursos sobre estudos por inquérito.
This section covers survey methods in general and has links to useful resources, but there are no learning materials as such.
For a good general introduction, see What is a survey? (American Statistical Association booklet, 68 pp., 2004 by Fritz Scheuren: combines as chapters a series of separate earlier pamphlets starting with What is a survey? by Robert Ferber, Chair, Paul Sheatsley, Anthony Turner and Joseph Waksberg, ASA, 1980 )
Flow diagram of the stages of a survey (from page 8 of Scheuren above). These days we should perhaps add a Stage 7: Secondary analysis
Tags: inquéritos
What is SPSS?
Posted by Armando Brito Mendes | Filed under estatística, materiais ensino, software
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Uma explicação para as ciências sociais
What is SPSS and what does it do?
SPSS consists of an integrated series of computer programs which enable the user to read data from questionnaire surveys and other sources (e.g. medical and administrative records) to manipulate them in various ways and to produce a wide range of statistical analyses and reports, together with documentation.
Most users will have access to SPSS via their college or workplace or by purchasing the Gradpack version (specially priced for students). Full details are on IBM SPSS Solutions for Education and there is a comparison table showing what is available in each version.
Tags: IBM SPSS Statistics, software estatístico
Summary guide to SPSS tutorials
Posted by Armando Brito Mendes | Filed under data sets, estatística, materiais ensino, software
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Bom site com vários recursos sobre a utilização do IBM SPSS
Catalogue of SPSS tutorials is an Excel *.xlms file containing a full listing (with hyperlinks) of all tutorial files.[may not be completely up-to-date]
Guide to pop-out menus shows all the screenshots for menus and sub-menus for Survey Analysis Workshop [may not be completely up-to-date and site has been re-organised, so needs a re-write, but still useful to show you what to expect]
There are more than 600 pages of downloadable tutorials arranged in four blocks.
Block 1: From questionnaire to SPSS saved file
1.1: The language of survey analysis
1.2: How do data relate to questionnaires?
1.3: Reading raw data into SPSS
1.4: Completing your data dictionary
1.5: Utilities [still in preparation]
Block 2: Analysing one variable
2.1: Nominal and ordinal variables
2.2: Interval scale variables
2.3: Data transformations
Block 3: Analysing two variables (and sometimes three)
3.1 Contingency tables
3.2 Three variables
3.3 Multiple response
3.4 Comparing means
3.5: Conditional transformations
Block 4: Hypothesis testing
[Still in preparation: provisional contents listed below: page also has links to some useful resources for statistical concepts]
Hypothesis testing
4.2a t-test and one way anova
4.2b Testing differences between three or more means
4.3 Chi-square (has one tutorial)
4.4 Regression and correlation
4.5 Association, structure and cause
SPSS files and documentation used for tutorials and exercises
Tags: análise de dados, IBM SPSS Statistics, inquéritos, software estatístico
Journeys in Survey Research
Posted by Armando Brito Mendes | Filed under data sets, estatística
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Bons conjunto de dados e explicações de como usar.
1: Close Encounters of the Fourth Kind: working with alien SPSS files
Data sets explored
• European Quality of Life Survey (2007)
• Understanding Society (2010)
• ONS Opinions Survey, Well‐Being Modules (2011)
(including unrestricted access data set for April 2011).
• NORC General Social Survey (GSS) (2008)
• British Social Attitudes (2011)
• British Social Attitudes (2004)
European Quality of Life Survey
European Quality of Life Survey (UKDS: 6299)
Understanding Society
Understanding Society (UKDS: SN 6614)
Commentary on Understanding Society 2010 (JFH)
ONS Opinions Survey, Well‐Being Modules
(including unrestricted access data set for April 2011)
Measuring National Well-being (ONS website)
Well‐Being Modules April-Sep 2011 (UKDS: SN6893)
Unrestricted Access Teaching Dataset (UKDS: SN 7146)
Introduction and Commentary: Unrestricted Access Teaching Dataset (JFH)
NORC General Social Survey (GSS)
1: Commentary on full NORC General Social Survey 2008
2: (Book) Sweet & Grace-Martin
Data Analysis with SPSS: A First Course in Applied Statistics (Pearson 2010)
(can be rented as e-book from CourseSmart)
Commentary on subset of General Social Survey 2008
3: (Book) Babbie, Halley, Wagner & Zaino
Adventures in Social Research: Data Analysis Using IBM SPSS Statistics (Sage 2103)
Commentary on GSS 2008 SPSS files for Babbie et al
British Social Attitudes (2011)
British Social Attitudes 2011 (UKDS: SN 7237)
Commentary on SPSS file for British Social Attitudes 2011 (JFH)
British Social Attitudes (2004)
(Book) Marsh & Elliott Exploring Data (Polity Press, 2008)
Review of Exploring Data (JFH)
Exploring Data Teaching Datasets (UKDS: SN 6096)
Commentary on SPSS files in Teaching Datasets (JFH)
European Social Survey (2002)
Notes on SPSS files for European Social Survey 2002
(private exchange between JFH and ESS team)
Tags: IBM SPSS Statistics
SPSS videos e trials
Posted by Armando Brito Mendes | Filed under estatística, software
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Um site da IBM com bastantes recursos sobre o SPSS
Software Trial: IBM SPSS Statistics Desktop
Start leveraging your data today to identify your best customers, forecast future trends, improve supplier performance, and more.
![Software Trial: IBM SPSS Text Analytics for Surveys Trial Software [US]](http://www.ibm.com/software/analytics/spss/products/statistics/images/icon-text-analysis-60x60.jpg){kind=icon}
Software Trial: IBM SPSS Text Analytics for Surveys Trial Software [US]
IBM SPSS Text Analytics for Surveys uses powerful natural language processing technologies specifically designed for survey text.
Software Trial: IBM SPSS Amos Trial
IBM SPSS Amos gives you the power to easily perform structural equation modeling (SEM).
Online Demo: IBM SPSS Regression in action
Watch how powerful regression techniques can help you discover hidden relationships in your data.
![Online Demo: Two-step cluster analysis: Find natural groups in your data [US]](http://www.ibm.com/software/analytics/images/offers/video-thumb/od_spssrc_ibm_spss_statistics_base_127x96.jpg)
Online Demo: Two-step cluster analysis: Find natural groups in your data [US]
Watch a short demonstration of the two-step cluster analysis technique in SPSS Statistics Base.
![Online Demo: Online Demo: Statistical analysis with confidence using IBM SPSS Statistics [US]](http://www.ibm.com/software/analytics/images/offers/video-thumb/od_spssrc_ibm_spss_statistics_product_overview_127x96.jpg)
Online Demo: Online Demo: Statistical analysis with confidence using IBM SPSS Statistics [US]
Explore the power of statistical analysis in your organization IBM Analytics IBM Analytics
![White Paper: White Paper: Better decision making under uncertain conditions [US]](http://www.ibm.com/software/analytics/images/thumbs/offers/wp_spssrc_simulation_modeling_in_ibm_spss_statistics_98x120.jpg)
White Paper: White Paper: Better decision making under uncertain conditions [US]
This paper describes Monte Carlo simulation, the value of this technique for risk analysis and how SPSS Statistics and its Monte Carlo simulation capabilities can help businesses assess for risk.
![White Paper: The Risk of Using Spreadsheets for Statistical Analysis [US]](http://www.ibm.com/software/analytics/elq/images/thumbs/IMW14297USEN.jpg)
White Paper: The Risk of Using Spreadsheets for Statistical Analysis [US]
Despite their popularity, spreadsheets may not be well suited for analysis and decision making. This paper explores why, and describes a better alternative.
Tags: análise de dados, IBM SPSS Statistics, software estatístico
Site oficial IBM SPSS
Posted by Armando Brito Mendes | Filed under estatística, software
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site com muita info. e documentação para o SPSS
What is IBM SPSS?
What if you could get deeper, more meaningful insights from your data and predict what is likely to happen next? IBM SPSS predictive analytics software offers advanced techniques in an easy-to-use package to help you find new opportunities, improve efficiency and minimize risk.
Statistical analysis and reporting
Address the entire analytical process: planning, data collection, analysis, reporting, and deployment.
Predictive modeling and data mining
Use powerful model-building, evaluation, and automation capabilities.
Decision management and deployment
Activate your analytics with advanced model management and analytic decision management on prem, on cloud or as hybrid.
Big data analytics
Analyze big data to gain predictive insights and build effective business strategies.
Tags: data mining, IBM SPSS Statistics
IFCS Cluster Benchmark Data Repository
Posted by Armando Brito Mendes | Filed under data sets
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alguns dados q podem ser utilizados em trabalhos
Welcome to the
IFCS Cluster Benchmark Data Repository
The aim of this Repository is to stimulate better practice in benchmarking (performance comparison of methods) for cluster analysis by providing a variety of well documented high quality datasets and simulation routines for use in practical benchmarking.
The repository collects datasets with and without given “true” clusterings. A particular feature of the repository is that every dataset comes with a comprehensive documentation, including information on the specific nature of the clustering problem in this dataset and the characteristics that useful clusters should fulfill, with scientific justification.
- Read more about the philosophy of the repository.
- Go directly to the list of available data sets.
Note: Up to May 15, 2017 a data set may be analyzed within the framework of a challenge! More information on this challenge is available here.
Tags: open data
Top Excel Tips For Data Analysts
Posted by Armando Brito Mendes | Filed under Bases de Dados, SAD - DSS
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Excelentes concelhos para utilização das últimas ferramentas implementadas no Excel.
Tags: Excel, programação em folha de cálculo
curso de KNIME
Posted by Armando Brito Mendes | Filed under mapas SIG's, materiais para profissionais, software, videos, visualização
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Muito bom curso de KNIME, é introdutório mas introduz um grande número de funcionalidades.
KNIME Online Self-Training
Welcome to the KNIME Self-training course. The focus of this document is to get you started with KNIME as quickly as possible and guide you through essential steps of advanced analytics with KNIME. Optional and very useful topics such as reporting, KNIME Server and database handling are also included to give you an idea of what else is possible with KNIME.
- Installing KNIME Analytics Platform and Extensions
- Data Import / Export and Database / Big Data
- ETL
- Visualization
- Advanced Analytics
- Reporting
- KNIME Server
Tags: análise de dados, big data, data mining, Knime, text mining
Decision trees: Do Splitting Rules Really Matter?
Posted by Armando Brito Mendes | Filed under Sem categoria
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Um bom texto sobre o critério de divisão em subgrupos nas árvores de decisão.
Do decision-tree splitting criteria matter? Contrary to popular opinion in data mining circles, our experience indicates that splitting criteria do matter; in fact, the difference between using the right rule and the wrong rule could add up to millions of dollars of lost opportunity.
So, why haven’t the differences been noticed? The answer is simple. When data sets are small and highly-accurate trees can be generated easily, the particular splitting rule does not matter. When your golf ball is one inch from the cup, which club or even which end you use is not important because you will be able to sink the ball in one stroke. Unfortunately, previous examinations of splitting rule performance, the ones that found no differences, did not look at data-mining problems with large data sets where obtaining a good answer is genuinely difficult.
When you are trying to detect fraud, identify borrowers who will declare bankruptcy in the next 12 months, target a direct mail campaign, or tackle other real-world business problems that do not admit of 90+ percent accuracy rates (with currently available data), the splitting rule you choose could materially affect the accuracy and value of your decision tree. Further, even when different splitting rules yield similarly accurate classifiers, the differences between them may still matter. With multiple classes, you might care how the errors are distributed across classes. Between two trees with equal overall error rates, you might prefer a tree that performs better on a particular class or classes. If the purpose of a decision tree is to yield insight into a causal process or into the structure of a database, splitting rules of similar accuracy can yield trees that vary greatly in their usefulness for interpreting and understanding the data.
This paper explores the key differences between three important splitting criteria: Gini, Twoing and Entropy, for three- and greater-level classification trees, and suggests how to choose the right one for a particular problem type. Although we can make recommendations as to which splitting rule is best suited to which type of problem, it is good practice to always use several splitting rules and compare the results. You should experiment with several different splitting rules and should expect different results from each. As you work with different types of data and problems, you will begin to learn which splitting rules typically work best for specific problem types. Nevertheless, you should never rely on a single rule alone; experimentation is always wise.
Gini, Twoing, and Entropy
The best known rules for binary recursive partitioning are Gini, Twoing, and Entropy. Because each rule represents a different philosophy as to the purpose of the decision tree, each grows a different style of tree.
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Tags: análise de dados, data mining
