DEPARTMENT OF POLITICAL SCIENCE AND INTERNATIONAL RELATIONS. Posc/Uapp 816 INTRODUCTION

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1 DEPARTMENT OF POLITICAL SCIENCE AND INTERNATIONAL RELATIONS Posc/Uapp 816 INTRODUCTION I. CLASS 1: AGENDA A. Course objectives and a pep talk 1. Statistics and substantive theory. B. Course procedures and guidelines C. Desktop computing 1. Windows 2. Files 3. Utilities II. III. A SUBSTANTIVE PROBLEM: A. The effects of the welfare state: 1. Recent changes in American welfare law reflect a widely held belief that the social assistance programs have done more harm than good. 2. This argument, which is really a debate between political conservatives and liberals, rests partially on statistical analysis. a. Each side invokes reams of supposedly scientific and objective data to support its claims. 3. As both citizens and policy analysts we ought to be able to judge the soundness of the evidence and methods. B. The welfare debate also illustrates how one can use statistical methods as a tool for investigating many interesting questions. COURSE PHILOSOPHY: A. This class rests on several propositions: 1. Each participant has a minimal familiarity with basic statistical concepts. a. Although we will review statistical inference, this review will go more smoothly if you have had at least one semester preparation. b. You can catch up by reading Agresti and Finlay, Statistical Methods for the Social Sciences, chapters 1 to 5. Alternatively, you might look at the material on the Public Management Statistics page of my internet site: c. Lectures from the Fall 1997 section of Public Management Statistics may be available in the reserve room of Morris Library. (If not, tough.) 2. Other than this background, I do not assume any knowledge of statistics and mathematics.

2 Posc/Uapp 816 Class 1 Notes Page 2 a. We will cover the main topic, regression analysis, from scratch. 3. Nor do I assume any one has any particular computing skills. a. If you have a personal computer, so much the better. b. But it is possible to do quite well by using the University s machines, which are located in numerous places throughout the campus. - A map is attached. There are many more sites, however. 4. Although I will attempt to draw substantive examples from all social and policy sciences, I may end up emphasizing political data. Still, you should be able to easily transfer the methods to your own disciplines. B. What you need. 1. An open mind and good attitude 2. Materials: a. Class notes and access to a personal computer. b. The Student Version of MINITAB for Windows, text and disks. c. Agresti and Finlay, Statistical Methods for Social Sciences, 3 rd edition. d. Sage Papers as listed in the syllabus e. If possible a statistical calculator C. Assignments and grades IV. APPLIED STATISTICS - AN OVERVIEW OF THE COURSE: A. Refer to the course guideline. B. We will cover methods for analyzing 1. Two categorical (nominal or ordinal scale) variables. 2. A quantitative dependent variable and one or more independent variables some of which may be categorical. 3. Time series: data collected at more or less regular intervals such as monthly employment figures. 4. (If time permits) a categorical dependent variable and one or more independent variables. C. The courses stresses mainly the interpretation of statistics and their underlying assumptions. 1. Less emphasis on computational formulas. 2. Very little attention to proofs or theory. V. THE INFORMATION NETWORK: A. First, let s make some distinctions 1. A terminal is a device with a monitor (screen) and keyboard and very little computing capacity and no user storage space. It s used to connect to or access a computer such as a mainframe (e.g., Copland). 2. A personal computer is a desktop machine that has central processor,

3 Posc/Uapp 816 Class 1 Notes Page 3 storage areas of various kinds, an operating system, and control of peripheral devices like printers and CD drives. 3. Terminal emulation: it is possible to program a personal computer so that it behaves or emulates a terminal. a. This is, in fact, a quite common practice. b. Most people at the University of Delaware have personal computers. When they want to read they in effect convert their machines to terminals. - This is why when using Pine, the University s main program, they cannot use many of the Windows features such as cutting and pasting. - Actually, there are some tricks as we ll see later. B. As ever one knows the world depends increasingly on the electronic transmission of information. This course is no exception. Quite apart from any statistical calculations you will be performing with a computer, you need to be familiar with electronic mail ( ) and the Internet C. The information network or virtual reality as the public calls it, consists of sets of files --documents, batches of numbers, images, computer programs and so forth--located in various places throughout the world. For our purposes it consists mostly of a class internet site or web page and data banks located in various institutions around the globe. D. How do you reach or access all of this information? 1. Figure 1 presents a simple overview. Figure 1: Information Network 2. One simply uses a terminal (that is, a simple video and keyboard) or personal computer programed to act like a terminal to send and visit

4 Posc/Uapp 816 Class 1 Notes Page 4 the class web site (the place where notes, data, announcements, and so forth are kept). E. Of course you have many choices or ways to connect to this information network. 1. A University of Delaware X-terminal. a. These devices, located in several places throughout the campus, consist of only a monitor and keyboard. They are not computers and cannot by themselves store information or run programs. If you use an X-terminal, any programs (e.g., ) that you start and any data or information that you collect will be stored on one of the University s mainframe or large computers (e.g., Copland, Brahms, Strauss). The terminal itself is not connected to any storage device. Although they are very useful, people rely more and more on personal computers. - You can, however, store data or files on the main system and retrieve them at a later time. 2. A University of Delaware desktop computer. a. See the attached map. b. Nearly all of the university s computers that are located in public sites are linked to the information network by high speed lines. c. With a PC one has several choices for computing and accessing the information network. The PC can be used as if it were a terminal-- that is a monitor and keyboard--that is linked to the mainframes and from there to the network. Or, it can run its own software to connect to the network. The latter option allows one to store data and text directly on the PC s disk drive. d. Most UD personal computers use Windows Your own computer that is linked via a modem to the University s network or to an Internet Service Provider s (ISP) network which in turn connects to the University. a. Your computer can act as terminal (see above) or run its own software that allow you to browse the internet and send and receive . F. Terminals versus personal computers. 1. Everyone will need access to a personal or desktop computer. 2. For some purposes, however, a terminal will suffice. a. Example: , browsing the internet. 3. As noted above, for some purposes a personal computer may be used as a terminal. a. For example, many people use the University s mainframe electronic mailing system, Pine, to receive and send messages. Pine runs on a central computer, Copland, and can be accessed from a PC that is connected via phone lines or cables to the University s

5 Posc/Uapp 816 Class 1 Notes Page 5 network. b. When doing so, however, the software--usually it will be telnet-- turns the computer into a simple (vanilla) terminal c. Consequently, I use the term telnet or telnet session to mean the use of a PC as a simple terminal. 4. Hence, it s important to know what each device does. a. Look at the attached figures. 5. When used as a terminal a PC loses many of the advantages of Windows. But one can run a Windows program such as MINITAB or WORD at the same time one has a telnet session open. And it s possible to copy information from the telnet window and paste it in the windows application. VI. VII. SOFTWARE: A. The term software refers of course to the program instructions computers use to perform various tasks. 1. Operating system (e.g., Windows) 2. Statistical program packages (e.g., MINITAB, SPSS) 3. Utilities (e.g., Notepad, Explorer) B. Software: public sites contain full versions of MINITAB and SPSS. 1. The Student Edition is a fully functional subset of the regular program that meets our needs. C. Try software before buying. 1. The Student version of MINITAB runs on Windows 3.1 and Installation directions are in book WINDOWS DEMONSTRATION: A. Some basics 1. If possible I will demonstrate these ideas with my laptop and/or some diagrams. 2. Note: there are many different ways of doing the same thing. 3. The desktop 4. Multiple windows a. Sizing, opening, closing, minimizing (hiding) windows b. Scrolling 5. Menu and task bars a. Dialogue boxes 6. Keeping track of windows: the title bar 7. GUIs 8. Mouse, pointer, cursor, insertion point B. Moving information from one window to another. 1. Highlighting with the mouse 2. Cutting and pasting to the clipboard

6 Posc/Uapp 816 Class 1 Notes Page 6 3. Notepad C. Help menus VIII. KEEPING DATA FOR FUTURE USE: A. It is important that you know how to save data and other information in proper formats. 1. I will, for example, give you data for use in one or more assignments. It s very helpful if you know how to save them instead of retyping the numbers each time. B. Folders and files 1. Think of folders as file drawers and files as separate pieces of information stored inside a drawer. 2. Files always have names with this general form: Name.extension a. Example: welfare.txt. Here Name is a descriptive title (e.g., the file refers to welfare data) and the extension, txt means that the file contains only characters and numbers. (See below.) C. Important: file types 1. Data (numbers, characters, images, etc.) are stored in different ways (formats) by different programs. You need to keep this in mind. 2. The type of format can usually be determined by examining the file name. 3. Types of files and the programs that produce them: a. Text files contain only numbers, letters, and other common typewriter characters. The extension is usually.txt b. Data files: files containing only numbers are sometimes called data files and have an extension.dat or.dat. c. MINITAB worksheets : when using a program such as MINITAB it is possible to save all of the information you are working on--the data, variable names, and other characteristics--in a worksheet. Once stored in this form only MINITAB can interpret the information. Thus, you can t use another program such as SPSS to open or read a MINITAB saved worksheet. - MINITAB worksheets use the extension.mtw or.mtw. d. Similarly, SPSS, another common program, stores worksheets in a special file format that only it understands. - In fact, many common programs such as spreadsheets (e.g., Lotus, Excel) all use special formats to save information. You can usually determine which program created the file by looking

7 Posc/Uapp 816 Class 1 Notes Page 7 at the extensions (e.g.,.xls,.wk). D. Public versus private desktop machines. 1. If you are using a public site, be sure to save your data and results on your own diskette. 2. Before starting make sure that you have a formatted disk. E. To format a disk with Windows See Figures 2 and 3 2. Make certain write tab is not in protected position. 3. Insert a blank (unused) disks into (usually) the A: drive 4. Double click on My Computer (on desktop) or click Start button (at lower left of monitor) and then Windows Explorer. 5. Double click on 31/2" Floppy 6. Follow the instructions: check full and type a label if you want one. F. Use Windows explorer to keep track of your files. IX. NEXT TIME: A. Windows and the basics of MINITAB and SPSS Go to Notes page Go to Statistics page