Developing a self-access and self-paced learning aid for teaching Statistics

Introduction

Background

The need to provide lectures and tutorials to a large number of undergraduate students in Statistics has triggered the idea of developing a computer assisted learning package. Several reasons were thought of. First, not many students realize the importance of this subject until they are in their final year. Second, background of the students in mathematics and statistics training varies and differs a lot. Those with A-level mathematics and/or statistics may find the subject boring while those from the humanities stream may find it too difficult to follow. The population of over 50 students in this class poses great difficulty to strike a balance between the two extremes. Lastly, as the students may find it necessary to apply statistics or statistical analysis in their final year of studies, it is worthwhile making the course open to all students for reference.

This was first appealed by a software package called Oracle Book, an user interface for the database management system Oracle, which is capable of handling hypertext, sound and video. However, the cost of providing every PC in the department a license was prohibitive, not to mention providing license for off-site access. The World Wide Web was first heard of about 18 months ago and it has attracted a lot of attention due to its capabilities; and more important, the cost. A Web server was set up about 14 months ago in the department; thereafter, a series of World Wide Web pages were prepared as an initial effort to achieving this need.

Objectives

• allowing students to read the course notes prior to attending class so that class meetings can be effectively used for more in-depth discussion of the topic areas concerned which cannot be achieved by computers, such as brain-storming;
• allowing self-paced learning not only for first year but all students when they need reference materials about the subject;
• reducing wastage as hardcopy of handouts is not necessary; and it is up to the students to print the relevant sections from the Web pages when needed;
• better/fuller utilization of resources. During the day, the computer labs will be used to its fullest extent and at night and during weekends, the servers will still be accessed by off-campus users;
• allowing two-way communication so that comments and queries can be fed back by the users while browsing through the information;
• capable of not only disseminating course materials but also other academic services such as testing;
• low cost.

How the System Works

Apart from other information that is served by the server, a section (a subdirectory) was created in the server to store teaching materials. Each topic will be stored in at least one file, supplemented by other graphics files. This will keep the size of each file relatively small for fast retrieval.

An example of a topic in Statistics, linear regression, is shown here [HREF2]. This example page has the following characteristics:

1. At the beginning of every page, a header with a link back to the home page of the server is provided. This is a consistent feature in all the pages of this server so that users can always go back to the home page if they feel get lost.

2. At the bottom of the page there is a link to the previous page and a link to the home page. This allows users to trace back where the current page comes from.

3. The contents of the material to be presented are organized in the way similar to a hardcopy handout. However, to capture the hypertext capability of the system, links are always provided when further explanation of the basic concepts or definitions is required. This can be a universal glossary page of a dedicated page.

4. All the graphics and equations are built into the pages using in-line images. Transparent images are generally used to make the layout resemble a printed copy and to reduce the possibility of a non-white (blank) background in the printed copies. However, colours are used in the figures to highlight features. Colours are generally not available on ordinary hardcopies.

5. A link is also provided at strategic locations in the page, depending on the length and complexity of the topic, for students to pose questions to the lecturer. This can be done by the mail to command which will trigger a mail composer window with the address of the sender and recipient filled.

6. Students are instructed and guided to use the Internet tools to access information from the servers. Tools that will be introduced include mail (Eudora), WWW browser (Netscape), FTP and news reader (Trumpet). Both specially designed handouts (hardcopy) and hands-on sessions are arranged so that they get actual experience in using these tools.

What Can't the System Do

1. It is still cumbersome to build equations in a Web page. It requires third party software packages to compose and then translate the equations into the displayable GIF format. If transparency is required, this three-step process often results in distortions in the images produced.

2. The Statistics subject requires many mathematical symbols and expressions to be displayed. Although equations can be composed and displayed as in-line images, there is often a need to use symbols and special characters in the text.

3. Further, even if some of the special characters in the extended ASCII character set can be called, there is a difference between what is shown in a PC and what is shown in a Macintosh computer.

   The following tables show a comparison between the difference in interpretation of the special characters from ASCII code 160 to 255.

   

   As can be seen not many symbols share the same code between the PC and the Mac environment. Many commonly used symbols such as summation, pi, one-quarter, one-half, superscript 2 and superscript 3 are not both displayable in a PC or Mac browser. This makes composing the pages difficult unless the type of computer with which student will use to read the materials is known. To overcome this, a series of GIF files, each containing only one symbol have to be generated in order that these symbols are displayed correctly on both platforms.

4. Tables are often required to present complex information. The subject Statistics also makes extensive use of tables. It used to pose a great difficulty to present tables in Web pages as it is more difficult to produce tables than equations by graphics software packages. The capability to interpret and display tables by Web browsers is only available in the very recent release (e.g. Mosaic 2.0 Alpha 8 of November 94 and Netscape Beta 1.1 of March 95). Users of older versions are still prevented from viewing tables.

5. Although the Web is capable of providing two-way communication (by incorporating forms or email links), it is not interactive and the two-way communication does not happen in real-time. Users may be frustrated if they do not get immediate help from the computer.

6. For students whose first language is not English, it may be difficult for them to express their queries in English via mail. This is especially so for technical subjects such as Statistics.

7. The system does not teach students how to operate the computer. Therefore, training students to get familiar with the computer is important. Only when a student has become familiar with the medium, and is able to participate in this discourse as transparently as in more familiar modes will its potential as a learning tool be fully realized.

Effectiveness as a Learning Aid

Self Paced and Self Access Learning

Students can exercise their discretion as to when and what to learn. This mode of learning is not only applicable in traditional education but also in open and distance learning. Currently, student can choose to work in the computer laboratories of the department which are all equipped with the necessary browsing tools.

The other side on the coin is that of the support that is provided. Currently the University's dial-up lines do not support SLIP- or PPP-type communication, meaning remote access is not possible yet. Apart from the department's own PC laboratories, other PCs which can be accessed by students in the University do not provide Internet facilities (except telnet and FTP). These to a large extent hinder the self-paced and self-access modes of learning.

Reduced Intimidation

Often in a classroom environment students are afraid to raise questions or to answer questions in order not to be intimidated in front of other peer learners. Learning individually in front of a computer reduces this kind of intimidation and students are more prepared to pose questions, however ignorant the question can be.

Interaction with Peers and Teachers

With the advent of electronic mail, there are more interactions between students and teachers and among students. However, experience shows that participation in news group discussion is still sparse. As explained above, students are generally timid to express their views or queries in front of the public; instead, they feel free to express in private (one to one) conversations.

Stimulate Learning Incentive

The attractive and user-friendly user interface of Web browsers (Mosaic, Netscape) stimulates students' incentive to dig into the Web. This usually starts with curiosity but when they realize the wealth of information that can be got from the Web, they will make good use of this wealth gradually. And this process does not stop at the end of their courses but will continue with their career.

The Feeling of One-To-One or even Many-To-One Learning

In a classroom the feeling is that the teacher's time is shared among a group of students and each student only receives only a fraction of the teacher's time (resource). With computer assisted learning, the feeling will resemble the apprentice type one-to-one teaching. The hypermedia effect, if properly constructed, will even generate a feeling of many-to-one teaching, i.e. many teachers are simultaneously teaching one student.

Better Utilization of Class Meetings

As an aid to traditional classroom teaching, the computer only takes away part of the functions of a classroom. Class meetings can then be used for other activities which cannot be achieved by the computer efficiently. This includes presentation of project by students, clarification of points, and brain-storming sessions.

Reduced Tedious Work Load

The use of computing technology as a teaching aid will surely reduce the tedious workload to the teachers, such as preparing, printing and distributing handouts, classroom management. Time can therefore be spent in more productive areas such as guidance to students and peer brain-storming. However, the production of courseware in Web format (HTML pages) can be difficult and time consuming as discussed above.

Less Constrained by Traditional Classroom Environment

A typical lecture or tutorial lasts for 45 minutes to 1 hour. However, the effective time available for the class is often far less. Late comers often disturb the progress of a class and so does noise. Other disturbance includes occasional equipment break-down, sick leave and so on. Worse, when time is up, little can be done to continue with the class as students may have to go to another class immediately. Very often, this kind of breaks causes a lot of abortive work.

Increased Responsibility

The replacement of some or all traditional class meetings by computer interactions does not mean reduced responsibility. Contrary, the teachers may bear more responsibility as there is bound to be more mail messages from the students raising questions either about the subject or about operating the computers; and the news groups also require frequent mediation.

Evaluation and Recommendations

Currently, it is still difficult to compose equations in HTML/HTML+. Tables can only be interpreted by Mosaic in a recent release (2.0a8), and Netscape 1.1 (March 95). It is envisaged that SGML should be able to overcome these difficulties when both the server and the client support SGML.

Composing and uploading HTML pages by teachers can be tricky. Some effort has to be made to make this process more smooth to reduce frustration. Currently, the pages are composed in a PC text editor and then uploaded to the unix server by FTP. To simplify this process, a HTML editor, such as an added-on template on MS Word, together with a NFS link between the unix server and PCs, is advocated. This means HTML pages can be directly written into the appropriate directory of the Web server.

Technically, experience shows that in a class with 30 concurrent users (486DX/66, 8M RAM) on the same Novell LAN segment accessing the same Web server (unix), over a campus backbone, degrades response time tremendously. The majority of the users only access straightforward text and graphics p and so on. Worse, when time is up, little can be done to continue wiages without movies. New technology should be developed to solve this traffic congestion problem, e.g. switching hub, fast ethernet or even ATM backbone.

If users access the server from off-campus computers via such equipment as a modem and a telephone line, the response of the servers is acceptable as the biggest bottleneck will then be in the telephone line. The speed of the telephone line may, however, affect the time needed to download graphics-intensive pages which in turn affects the overall performance of the Web.

The Web server is a necessary but not sufficient facility if on-line education is to be adopted seriously due to its limited interactivity. Supplementing this service should include others such as electronic mail, news group and conferencing facilities.

It is still more difficult to administer tests for this kind of subject (Statistics) due to the involvement of equations and tables. A page, comprising multiple-choice and fill-in-the-blank questions using CGI form and Perl script, has been set up as a quiz to a group of 150 students in another subject Computing as shown [HREF3]. The script behind the form will append the answers, in the form of a comma delimited line per student, to a pre-defined file (ASCII format), which can then be imported into a spreadsheet (Excel or Lotus 123) for marking and analysis. Initially, this proves very effective and time-saving. Further research and development work have to be done to incorporate more features such as random selection of questions and security.

Providing training to both teachers and student is essential. Familiarity of the operations of the whole system, which includes hardware setup and software manipulation of the browsers (Mosaic), news reader, electronic mail and conferencing, is necessary in order to exploit the full potential of this technology.

To make full use of the Web system as a hypermedia learning aid, the very least that can be done is to distribute materials on diskettes (or CD-ROMS) and let students browse the materials in a standalone mode. Of course, this should be the last resort as one very important element of the Web is the 'link' that is inherent in the system.

Conclusions

Development work on the World Wide Web is currently undertaken in the Department of Building and Real Estate in (i) document management in a closed environment, (ii) administering tests, (iii) enhancing interactivity, and (iv) security issues.

References

Krol, E. (1992) The Whole Internet. O'Rilley & Associates Inc.

Mason, R. and Kaye, A. (1988) Mindweave: Communication, computers and distance education. London: Pergamon Press.

Standard Generalized Markup Language, http://www.digital.com/gnn/wic/comput.39.html

Hypertext References

HREF1

http://www.bre.polyu.edu.hk/DoBRE/Staff/bssmak/

HREF2

http://www.scu.edu.au/ausweb95/papers/education/mak/aw01-01-2.html

HREF3

http://www.scu.edu.au/ausweb95/papers/education/mak/aw01-01-4.html

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