Path: utzoo!attcan!uunet!midway!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!uupsi!sunic!news.funet.fi!funic!santra!cs.hut.fi!juh From: juh@cs.hut.fi (Juha Hyv|nen) Newsgroups: comp.edu Subject: Re: Automatic checking the students' answers Message-ID: Date: 31 Oct 90 13:59:26 GMT References: Sender: news@santra.uucp (Cnews - USENET news system) Distribution: comp Organization: Helsinki University of Technology, Finland Lines: 222 In-Reply-To: eibo@rzsun3.informatik.uni-hamburg.de's message of 22 Oct 90 11:56:16 GMT [ This discussion is beginning to be about the nature of learning and education as a process. Eibo seems to argue that the educational system (practices) should be changed. My original question (about automatic generation of individualized homework questions and the checking of the answers) could be regarded as an attempt to "patch" the existing practice on my part where I have a chance to do it. I believe Eibo and I are talking about different things. My arguments are not valid if the purpose were to change the system. They might be regarded as an attempt to defend the system. And I think Eibo's arguments are not valid in the context that this discussion started (using the computer to help in checking the homework). Maybe we should discuss about how the computers should be used in education and how they should not. Anyone want to start that? Eibo? Or is that old news to everyone (but me)? ] From: eibo@rzsun3.informatik.uni-hamburg.de (Eibo Thieme) +------------------------ ! >To make sure everyone is doing their homework, it has to be checked. ! ! Here we are at the verge of philosophy of education. I don't believe ! it to be sensible to enforce people doing there homework. !........................ We are making them do their homework because we want them to pass the course the first time they take the final exam. If doing homework were voluntary, then most students would not do it, but everyone *will* pass the exam, eventually -- even if they are not interested -- because they need to (in order to graduate). Do you think it would be sensible to give some incentive to do their homework? The points from homework could be added to the final exam points. (Now the only incentive is that if you do not do your homework, you do not pass the course. And those who do homework very well get a bonus.) Do you think the final exam (in its traditional form) is a sensible way to measure the students' skills? +------------------------ ! You can only learn if you want to know. !........................ You can (only) learn if you want to know *more*. +------------------------ ! If you force them to do their homework they will learn as much and as ! intensely as required to do it, instead of wanting to know ever more as ! they acquire a higher proficiency. !........................ First, the student knows "nothing". How can he want to learn more? Homework helps the student to learn something to start with. Then, if he finds it interesting, he can study more. And how is the student to know when he has reached even the required level? The time the student can devote to one course is limited. +------------------------ ! There might be some people who would ! not loose their interest in learning, even under such hard conditions, !........................ Hard? It is easier for the students to understand if they learn by doing. Are you saying that those who would *otherwise* be interested might loose their interest? I do not agree. Helping the studets to understand should *increase* their interest in the subject because they find out it was not as difficult as it first sounded. +------------------------ ! I don't want anyone to succeed at the university ! who needs to be pushed forward all the time. !........................ We are not pushing them. We are guiding them to help them learn (by doing). We provide them hints of the minimal level everyone is supposed to reach. +------------------------ ! >Presently, checking the homework is done by a person. Last spring, ! >over 500 students took part in the course. That meant that a total of ! >500 students x 5 parts x 4 questions = 10,000 answers had to be ! >checked (and the results registered). At the rate of checking one ! >answer a minute it would take over 160 hours to check all the answers. ! >That is one working month! I think that the time should be spent ! >teaching than doing a routine job that could be done by a computer. ! ! Whenever you discover anything not operable you should first think of it ! as wrong instead of considering a computer to do what you can't. !........................ From the students' point of view, the (current) homework system looks like being an improvement over the previous system. Last spring was the first time we used homework questions. Before, we had programming assignments. Some statistics on final exam results: final exam results year 1989 year 1990 ----------- ----------- 5 (excellent) 24 (~17%) 81 (~20%) 4 20 (~14%) 72 (~17%) 3 23 (~16%) 85 (~20%) 2 17 (~12%) 64 (~15%) 1 18 (~13%) 45 (~11%) 0 (failed) 38 (~27%) 68 (~16%) ----------- ---------- total 140 415 The final exam is held four times a year. The statistics are from the first exam held right after the course was over. (The students have three attempts to pass the exam; actually four, because nobody is counting.) There are two things to note (year 1990): The number of students who took the exam right after the course was over was very high. Before, the number of students was more evenly distributed with the four exams (with the first two being the largest). Therefore, the students seemed to be more motivated than before. Students got better grades overall and especially the percentage of zeros dropped. (I do not have statistics from other exams, but the percentage of zeros has been somewhere between 25 to 35 %.) In addition, there was a strong correlation between the homework results and the final exam result. Did the students really learn more or were they simply better prepared to answer to final exam questions? +------------------------ ! I think your questions are alright, but they should be answerable by ! everyone who took the course. You could certainly devise more realistic ! questions where the student had to extract the formalized problem first ! but that's not I am up to. To ask questions in the first place is a ! hindrance, give your students the opportunity to show they know by ! acting in their environment. Offer interesting projects, give intersting ! problems to solve, give your students the opportunity to teach, as this ! makes them aware of their knowledge. !........................ Aren't the questions answerable? [Begin the provocation...] Interesting projects and problems, and teaching require too much time *from the students*, because everyone would have to (e.g.) teach every algorithm in order to learn it. (If they do not have to teach every algorithm, they are interested only as long as they have completed their part. I *know*.) And how do we give those 500 inexperienced and unconfident students the opportunity to teach (=time and place)? How do we evaluate those *10,000* lessons given by the students? (The figure 10,000 is the number of answers to homework questions last spring.) Let's say it takes 15 minutes to teach an algorithm. So, it takes 15 working months to grade the students!!! And that has to be done in one semester (3.5 months, 4 hours a week). Now we have 1.5 people teaching the course. That would have to be increased to 40!!! Do you call that operable? Yes, we could have the students grade the lessons themselves. [...now back to less provocative discussion, I hope.] We simply want to know whether the students can solve the problem using a specific method or not. Do you think that is unreasonable? The students are required to understand how all the different algorithms work. It is *not* sufficient to know the properties of the algorithms. The properties are *memorized facts* used to select the right algorithm to solve an "interesting" (real) problem. To be able to select the right algorithm, you have to know its properties. To know the properties of an algorithm, you have to memorize them. (You have to remember them.) To understand a property of an algorithm, you have to understand how the algorithm works. To understand how an algorithm works, you either have to implement and test it or do it manually a few times. (Implementing requires more effort.) To understand why an algorithm has a certain property, you have to be able to do it manually. (To understand how the property was derived.) To be able to do it manually, you have to do it manually. (Confusing?) If you understand why an algorithm has certain properties, you can safely apply it in situations where it was not intended to be used. (Or nobody ever thought of using it there before.) If you understand how an algorithm works you can modify it to be used in situations where it was not intended to be used. The students need to understand "why" in order not to make a wrong decision (when selecting an algorithm in real life). If you know how something is done it is easier to figure out why. And even if you do not understand the "why" you will not forget the "how" completely because you have done it at least once. If you later need to understand the "why", you can propably figure it out because you know the "how". BTW, doing an algorithm manually is in effect the same as teaching the algorithm to others! In both cases, you (should) show how the algorithm works! / (.___o .. /_/ ___/ Juha Hyvonen ! / ! !/ ) ! juh@hutcs.hut.fi ------