85173 - ANALYSIS OF CATEGORICAL DATA

Conoscenze e abilità da conseguire

By the end of the course the student acquires the knowledge of descriptive and probabilistic methods for the analysis of contingency tables. The student is also able to choose the best method to perform multivariate analyses of a given categorical dataset and to interpret the obtained results.

Contenuti

Introduction (2 hours)

• Data matrices and contingency tables
• Descriptive and inferential techniques for the analysis of contingency tables

Probabilistic methods (11 hours)

• Probability structure for contingency tables
• Loglinear models for contingency tables
• Model specification
• Parameter estimation and interpretation
• Goodness-of-fit measures
• Model selection and comparison
• Diagnostics for checking models

Descriptive methods (11 hours)

• Geometric concepts in multidimensional space
• Matrix decompositions (spectral, singular value), low-rank matrix approximation and multidimensional analysis
• Theory and algebra of simple correspondence analysis
• Canonical correlation analysis of contingency tables
• Multiple correspondence analysis

R functions and packages for the analysis of contingency tables (6 hours)

• Syntax, usage and output of functions and packages available in the R environment for the analysis of contingency tables
• Examples of analyses based on the use of such functions and packages

The reported number of hours is an estimate which takes account of both theoretical and practical lessons. Practical lessons will take place in a computer laboratory on a weekly basis, starting from the third week of lesson.

Testi/Bibliografia

Compulsory readings

• A. Agresti. Categorical data analysis, Second edition. Hoboken: John Wiley & Sons, 2002. Chapters 1-3, 8-9
• M. Greenacre. Theory and applications of correspondence analysis. London: Academic Press, 1984. Chapters 1-5
• O. Nenadic, M. Greenacre. Correspondence analysis in R, with two- and three-dimensional graphics: the ca package. Journal of Statistical Software. May 2007, Volume 20, Issue 3
• Additional readings concerning topics not included in the recommended textbooks (to be announced during the lessons)

Additional materials useful for the preparation of the exam will be made available on the platform "Insegnamenti online - Supporto online alla didattica" (https://iol.unibo.it/ ) for all enrolled students. In order to have access to this platform, students must use their username and password.

For the preparation of the exam students are supposed to use all the compulsory readings.

Metodi didattici

Theoretical lessons in a lecture hall and practical lessons in a computer laboratory through the R computing package. R scrips used during the practical lessons will be made available on the platform "Insegnamenti online - Supporto online alla didattica" (https://iol.unibo.it/ ) for all enrolled students.

Although attending lessons is not mandatory, it is strongly recommended.

Modalità di verifica e valutazione dell'apprendimento

The exam tests the qualifications of each student both on a theoretical and a practical level.

The exam is written, lasts two hours and takes place in a lecture hall. It is composed of four parts with open questions: some concern the theoretical aspects of the statistical methods, some other are mainly focused on the ability of using methods for data analysis and interpreting results. These latter questions require solving numerical exercises. In some cases, results obtained from the analysis of a real data set using the R packages illustrated during the practical lessons may be provided. Consulting textbooks or notes during the written exam is not allowed. A pocket calculator is necessary. The maximum mark for each part is 8. The overall mark of the exam is given by the sum of the marks in the four parts, which is expressed on a scale of 30.

Further useful information about the exams

• In order to take the exam, students are required to put their names down for the exam through Almaesami platform.
• Exams can only be taken in the official exam sessions.
• An identity card (or the UNIBO student card) is required to take part in the exam.
• Students will not be permitted to use any electronical device (mobile phones, smart watches, electronical data storage devices, etc.). If you have your mobile phone with you during an exam, you should turn it off and place it under your chair in the exam venue. Students found with a mobile phone on their person are in breach of University regulations and they will not be allowed to finish the exam.
  

Third call - September 4, 2020

• The exam will be written and will take place online through the Zoom platform for all students.
• Students who want to take the exam on this call are kindly requested to check the information about how to take a written exam online via Zoom which is available at the webpage https://www.unibo.it/en/services-and-opportunities/online-services/online-services-for-students-1/lessons-and-exams-online.
• The exam requires the use of pen and paper.
• Before taking the exam, students must install a free app or software on their smartphone with which they can scan their paper and save it as a single document (PDF format recommended). Students should also try creating a single file with two or more photos by using the scanning app so as to avoid any technical issues at the end of the exam.
• During the exam, students need to be by themselves in a well-lit room; they need to have some blank sheets of paper, a pen and an identity document with a photo, and set up a webcam so that their face and hands and sheets of paper are visible. They must write their name, surname and matriculation number on each sheet of the paper and on each page. Consulting textbooks, notes and electronical devices (mobile phones, smart watches, electronical data storage devices, etc.) during the exam is not allowed. Microphones and cameras of all students have to stay on and students must remain silent during the exam. Students' smartphones have to be in sight and face down and, if requested by the teacher, should be used to provide a 360-degree view of the room. The teacher will supervise students and will answer any questions via chat. The teacher must be able to access students' cameras at any time during the exam.The teacher may ask to check on a student via the webcam of the Zoom meeting where the student is taking the exam (or via smartphone).
• When the time is up, students must put down their pen and stop writing. At the teacher’s request, they must show each sheet of the paper they have written via webcam. Each student must open the scanning app on their smartphone, take pictures of each sheet of the paper so as to create a single file for their exam, and saved it with the name Surname.pdf. Then, they have to send the so-obtained document (PDF format recommended) to the teacher using their institutional email address (@studio.unibo.it). The teacher will check that all e-mails have been successfully received and will announce the end of the exam.
  

Strumenti a supporto della didattica

Some explanations are given by using slides, which will be made available on the platform "Insegnamenti online - Supporto online alla didattica" (https://iol.unibo.it/ ) for all enrolled students.

Orario di ricevimento

Consulta il sito web di Gabriele Soffritti