Re: Evaluating students
In article <[EMAIL PROTECTED]>, dennis roberts <[EMAIL PROTECTED]> wrote: >i would also like to again make a push for correct answers rising to the >approximate same level of importance as process ... we just cannot take >lightly the fact that when someone gets the wrong answer, saying that this >is not THAT important ... I agree. Getting the right answer is, after all, the ultimate objective. Achieving this objective requires more than just a knowledge of the correct process - it also requires the ability to carry out this process reliably. Ignoring this seems like an "academic" bias towards knowlege as opposed to skill. For real work, including academic work, the skills are equally important. Furthermore, avoiding the wrong answer often involves wider knowledge than just that of the process. I have many, many times seen answers from students who knew the correct process, but just made a silly arithmetic mistake - and then failed to realize that the resulting answer was ridiculous. Some students are unfazed by probabilities that are greater than one, by negative variances, and by estimates that are obviously completely ridiculous. Giving full or mostly full credit for such answers on the basis that they "just" made an arithmetic error does not seem to me to be reasonable. Radford Neal Radford M. Neal [EMAIL PROTECTED] Dept. of Statistics and Dept. of Computer Science [EMAIL PROTECTED] University of Toronto http://www.cs.utoronto.ca/~radford = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Check out this link
It returns the message "The page cannot be found" Could you please check it. TIA ellen "Student" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Hello, List > > This link might be useful for students: > > http://help-for-students.port5.com/professor.html > > Student > > > > > > = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Evaluating students
the general problems evaluating students are how much time do you have for (say) exams, what can be reasonably expected that students will be able to do with that amount of time, what content can you examine on, and ... what sort of formats do you opt for with your exams in statistics, let's say you have covered several inferential topics from midterm to the end ... maybe some difference in means situations using t tests and building CIs, perhaps something about tests and CIs about proportions, and then a unit on ANOVA (note: the above are just examples) how much can you have them do ... in an open ended way ... in an hour? for example, i can easily visualize having very small sets of data ... that they work with for each of the above ... with appropriate distribution tables at hand ... giving written explanations of their results ... but, is it realistic to expect them to do something from all of these in one hour? i really doubt it so, in the final analysis, ANY test (no matter what the format) is just a sample of all the things you could ask them to do ... thus, no matter what you do and what they show ... you are still left with many unanswered questions about their knowledge and skill i think it would be fair to say that in having students work problems and show their work ... you do get a better idea of their knowledge of THAT but, generally, you are not able to have as widespread coverage of the material you have covered since the last test ... than perhaps with some recognition item approach ... where you can cover more but, clearly, you get less information about any specific piece of knowledge or skill ultimately, it is a tradeoff ... and, as i think someone else mentioned, if the instructor is also strapped with large classes (which is so common these days) ... practical considerations enter that weigh perhaps more heavily than pedagogic best practice dennis roberts, penn state university educational psychology, 8148632401 http://roberts.ed.psu.edu/users/droberts/drober~1.htm = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Introductory Statistics text
At 07:34 PM 11/18/01 -0800, Melady Preece wrote: >I am looking for a new and improved Statistics text for an introductory (3rd >year) stats course for psychology majors...I would welcome any >suggestions/reviews, etc. > >Melady Preece improved over what? what are you using? what don't you like about it? is software used and if so, does the book you are using (or would like to use) help out in this? >= >Instructions for joining and leaving this list and remarks about >the problem of INAPPROPRIATE MESSAGES are available at > http://jse.stat.ncsu.edu/ >= == dennis roberts, penn state university educational psychology, 8148632401 http://roberts.ed.psu.edu/users/droberts/drober~1.htm = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Introductory Statistics text
I am looking for a new and improved Statistics text for an introductory (3rd year) stats course for psychology majors...I would welcome any suggestions/reviews, etc. Melady Preece = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Antigen found Win32 virus
Antigen for Exchange found methods.pif infected with Win32 virus. The file is currently Deleted. The message, "I am teaching the students", was sent from Hughlene Lucas and was discovered in IMC Queues\Inbound located at DMH/CO/CO07. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
InterScan NT Alert
Receiver, InterScan has detected virus(es) in the e-mail attachment. The virus has been deleted by AIP virus scanner. Date: Sun, 18 Nov 2001 20:16:48 -0500 Method: Mail From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> <[EMAIL PROTECTED]> <[EMAIL PROTECTED]> <[EMAIL PROTECTED]> File: methods.pif Action: deleted Virus: PE_MAGISTR.B = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: I am teaching the students
The attachment to this message contains a virus. Ronny Richardson At 07:12 PM 11/18/2001 -0500, you wrote: >I think it is great for the students to be able to analyze more easily using a calculator, but I feel that they must know what the calculator is finding for them. > This unit fits into the overall curriculum for Algebra II as determined by the State Department of Public Instruction. > > >Attachment Converted: "d:\eudora\attach\InterScan_SafeStamp.txt" > = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Antigen found Win32 virus
Title: Antigen found Win32 virus Antigen for Exchange found methods.pif infected with Win32 virus. The file is currently Deleted. The message, "I am teaching the students", was sent from Hughlene Lucas and was discovered in IMC Queues\Inbound located at CMHMAIL/CMHMAIL/EXCHANGE2.
An email sent to you was removed due to it's =*.pif attachment
We're sorry, but for your protection we are automatically filtering out file attachments which are commonly used by email viruses to spread their malicious code. Our Email Anti-Virus Filter found methods.pif matching =*.pif file filter. The file is currently Removed. The message, "I am teaching the students", was sent from Hughlene Lucas and was discovered in IMC Queues\Inbound located at University of Missouri/UMX/UMX-MAIL02. If you are expecting and needing the attached file which has been deleted, please recontact the sender and ask them to save the attachment with a file extension which is 'non-executable', such as *.txt, and then have them resend you the attachment to you in a new email message. Once you receive the new message, simply save the attachment with it's original file extension to your hard drive and then open the file in order to execute the program. If you are expecting a compressed, 'zipped' file, containing executable files which has been filtered, please recontact the sender, ask them to password protect the zipped file and then resend the attachment to you along with the zipped file password. Once you receive the new message, simply save the attachment to your hard drive and then open the file with the password in order to unzip the compressed files. Thank you, UMC Email Administration = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
I am teaching the students
I think it is great for the students to be able to analyze more easily using a calculator, but I feel that they must know what the calculator is finding for them. This unit fits into the overall curriculum for Algebra II as determined by the State Department of Public Instruction. methods.pif Description: Binary data
Re: Evaluating students
At 02:45 PM 11/18/01 -0700, Roy St Laurent wrote: >Comments interspersed below... > > >Sure, I wouldn't give a student full credit if their process was correct but >their >final result was wrong. But an answer that shows me they know the process >but have the wrong final result is worth MUCH, MUCH more than an answer >that has the final result but provides me with no clue as to whether they >understand >how to get it. again ... this makes sense with one item ... it does not necessarily make sense with multiple items > > > > 2. that answers without any OTHER supplied information on the part of the > > examinee can't be taken as "knowledge" when, it (sometimes) can be > > > > what if you asked on an exam ... the following: > > > > 1. what is the mean of 10, 9, 8, 8 and 7? _ > > > > 2. what is the mean of 27, 23, 19, 17 and 16? > > > > 3. what is the mean of 332, 234, 198, 239, and 200? _ > > > > 4. what is the mean of 23.4, 19.8, 23.1, 19.0, and 26.4? _ > > > > and, for each of 1 to 4 ... they put down in the blanks, the correct > answers > > > > would you be willing to say that they know how to calculate the mean ... > > ie, they know the process that is needed (and can implement it)? > >Depending upon whether they have access to a calculator and other information, >I may or may not be able to conclude that they know how to calculate a mean. >More importantly, the example you give is the worst possible example of how >to write an examination. Why should I ask them to do four calculations when >one, with properly supported work, will suffice? AND will permit me to better >assess their understanding of the calculation. you miss the point entirely ... i did not suggest that the items above would be specific ones i would put on any exam ... it was to illustrate that one CAN determine "skill" without having work shown ... if someone did the above without the aid of a calculator ... i think you have to admit they understand the process ... now, if you are talking about efficient test item administration ... surely, one item that has to be worked out is much faster to give ... it is not necessarily faster to take necessaril and, surely, it is not faster to grade ... especially with more complex problems >BTW, I would be inclined to ask questions that minimize but do not eliminate >calculations >in favor of questions that ask students to tell me what the quantity >calculated >means in >the context of a data analysis (or other) problem. Though I would not >eliminate >evaluation >of students ability to calculate, I agree with Herman that we need to >focus more >on >students' understanding of concepts. sure, agreed ... but lots of statistical work involves as part of the concept ... calculations ... when doing significance tests for example ... THE calculation makes all the difference in whether you are able to retain or reject some null value ... > > > > i think you would EVEN though there is no other supporting process > > information given by the examinee > > > > so, the statement that no credit should be given when there is no > > supporting other evidence (ie, the process is shown) ... can't be > > considered necessarily valid > > > > the problem here is NOT that no supporting evidence is given, the problem > > is that with ONLY ONE instance of some given concept/skill that we are > > attempting to assess on the part of the examinee, you are not nearly as > > sure given only ONE CORRECT RESPONSE to one item ... whether it could have > > been an answer because of real knowledge or, just happens to be the right > > answer that was arrived at (luckily for the examinee) through some faulty > > process > >Even several instances of correct responses of the sort you described above >do not provide necessarily convincing evidence, and they require more >unnecessary >busy-work for the student. (I am not stricly opposed to "busy-work" in the >context >of student learning of a concept or calculation, but I am opposed to it in the >context of evaluation >of student learning.) the bottom line is that ... for any single item ... whether supporting work is given or not ... one cannot be sure about the level of knowledge of the examinee ... showing work when only a single item is given does give one a higher p value of knowing but .. never ... for sure of course, there is also in interaction with the complexity of the problem ... the more complex the item which requires many more steps in the process, the less likely someone can get to the final point correctly without knowing the correct intermediate steps ... for much simpler problems ... even shown work could have been lucked into ... i would also like to again make a push for correct answers rising to the approximate same level of importance as process ... we just cannot take lightly the fact that when someone gets the wrong answer, saying that this is not THAT important ... there are many many situations w
Re: Evaluating students
Comments interspersed below... Dennis Roberts wrote: > At 08:56 AM 11/16/01 -0700, Roy St Laurent wrote: > >It's not clear to me whether recent posters are serious about these > >examples, but > >I will reiterate my previous post: > > > >For most mathematics / statistics examinations, the "answer" to a > >question is the > >*process* by which the student obtains the incidental final number or > >result. > >The result itself is most often just not that important to evaluating > >students' > >understanding or knowledge of the subject. And therefore an unsupported > > > >or lucky answer is worth nothing. > > the problems with the above are twofold: > > 1. this assumes that correct answers are NOT important ... (which believe > me if you are getting change from a cashier, etc. etc. ... ARE ... we just > cannot say that knowing the process but not being able to come up with a > correct answer ... = good performance) Sure, I wouldn't give a student full credit if their process was correct but their final result was wrong. But an answer that shows me they know the process but have the wrong final result is worth MUCH, MUCH more than an answer that has the final result but provides me with no clue as to whether they understand how to get it. > > 2. that answers without any OTHER supplied information on the part of the > examinee can't be taken as "knowledge" when, it (sometimes) can be > > what if you asked on an exam ... the following: > > 1. what is the mean of 10, 9, 8, 8 and 7? _ > > 2. what is the mean of 27, 23, 19, 17 and 16? > > 3. what is the mean of 332, 234, 198, 239, and 200? _ > > 4. what is the mean of 23.4, 19.8, 23.1, 19.0, and 26.4? _ > > and, for each of 1 to 4 ... they put down in the blanks, the correct answers > > would you be willing to say that they know how to calculate the mean ... > ie, they know the process that is needed (and can implement it)? Depending upon whether they have access to a calculator and other information, I may or may not be able to conclude that they know how to calculate a mean. More importantly, the example you give is the worst possible example of how to write an examination. Why should I ask them to do four calculations when one, with properly supported work, will suffice? AND will permit me to better assess their understanding of the calculation. BTW, I would be inclined to ask questions that minimize but do not eliminate calculations in favor of questions that ask students to tell me what the quantity calculated means in the context of a data analysis (or other) problem. Though I would not eliminate evaluation of students ability to calculate, I agree with Herman that we need to focus more on students' understanding of concepts. > > i think you would EVEN though there is no other supporting process > information given by the examinee > > so, the statement that no credit should be given when there is no > supporting other evidence (ie, the process is shown) ... can't be > considered necessarily valid > > the problem here is NOT that no supporting evidence is given, the problem > is that with ONLY ONE instance of some given concept/skill that we are > attempting to assess on the part of the examinee, you are not nearly as > sure given only ONE CORRECT RESPONSE to one item ... whether it could have > been an answer because of real knowledge or, just happens to be the right > answer that was arrived at (luckily for the examinee) through some faulty > process Even several instances of correct responses of the sort you described above do not provide necessarily convincing evidence, and they require more unnecessary busy-work for the student. (I am not stricly opposed to "busy-work" in the context of student learning of a concept or calculation, but I am opposed to it in the context of evaluation of student learning.) > ___ > dennis roberts, educational psychology, penn state university > 208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED] > http://roberts.ed.psu.edu/users/droberts/drober~1.htm > > = > Instructions for joining and leaving this list and remarks about > the problem of INAPPROPRIATE MESSAGES are available at > http://jse.stat.ncsu.edu/ > = -- Roy St. Laurent Mathematics & Statistics Northern Arizona University http//odin.math.nau.edu/~rts = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Check out this link
Hello, List This link might be useful for students: http://help-for-students.port5.com/professor.html Student = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: [HELP NEEDED] What is the best technique to analyze the following experiment?
On 16 Nov 2001 09:34:52 -0800, [EMAIL PROTECTED] (S.) wrote: > I performed the following experiment: > > Each user (U) used several interfaces (I). Both U and I are to be > treated as random factors. For each U and I combination, time (T), > errors (E) and satisfaction (S) were measured. The data looks > something like: > > U I T E S > --- --- --- --- --- > U1I1100 1090 > U1I2200 2080 > U1I3300 3070 > U1I4400 4060 > U2I1102 1191 > U2I2198 1881 > U2I5500 5050 > U2I6600 6040 > . > . > . > etc. > > Please note that NOT all the users used all the interfaces. > > The question is: I wish to find the correlations between T, E and S > (viz., nullify the effects of U and I). What is the best statistical > method of doing this? I think something along the lines of Anova or For the little bit of data shown, the variable *I* has a huge effect, with R-squared of maybe 0.99 with each of the three variables, T, E and S, and that happens while I call it a continuous variable. So it would be just as important, with a waste of degrees of freedom, if it is used as categories; the table shows it coded as categories, I-1 to I-6. High R-squared puts you into the situation where subtle choices of model can make a difference. Is it appropriate to remove the effect of *I* by subtraction, or by division? - by category, or by treating it as continuous? > Variance Components should do that trick... I have SPSS, so any advice > on how to interpret the output will be most appreciated (please bear > in mind that I do not have a degree in statistics). If it is strictly correlation that you want, you can ask for the intercorrelations, while partial ling out the U and I variables. If *I* and U are to be partialled-out as categories, you can create a set of dummy variables, and partial-out those. The result that you get will *not* be robust against scaling variations (linear versus multiplicative, for instance). That is a consequence of the high R-squared and the range of numbers that you have. I suspect that the observed R-squared values might vary in a major way if you just change the raw data by a few points, too -- Note that prediction with an R-squared of 0.99 has *twice* the error of an R-squared of 0.995, and so on; that is approximately the same as the difference between 0.1 and 0.2, in certain, practical consequences. If it will please you to reduce the eventual intercorrelations to zero, a proper strategy *might* be to try alternative models to see if you can produce that result. Of course, in practice, it should be a great deal of help to know what the variables actually, are, and how they are scored, etc., to know what transformations are logical and appropriate. I suspect that data, as stated, leave out some conventional standardization, and so the observed correlations are mainly artifacts. -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Usability of skills and knowledge
In article <[EMAIL PROTECTED]>, Rolf Dalin <[EMAIL PROTECTED]> wrote: >In a discussion about the desired direction of development of intro >level statistics courses, a group where I am a member came to a >preliminary agreement that It is important to develop applied >statistics. I started to think about that concept in terms of main goals >of a course. The two main goals I suggest are >1. abilities to use statistics in scientific work >2. ability to study statistics further I would differ on both. In fact, there should not be ONE "introductory level" statistics course, but the introduction should be at the highest level of mathematical understanding which will be attained. What the non-expert need most of all is to understand probability, probability modeling, and the evaluation of consequences, and to be able to FORMULATE investigations in this manner. The usual study by the one applying statistics of methods is greatly to be deplored; it is often necessary to devise new methods for a particular problem, and the one who does not understand theory is very likely to mess this up. Understanding need not require the full mathematics to derive results. It is totally irrelevant if the student knows how to compute a mean or a standard deviation. From some of the postings here, it seems clear that not all know what they mean and why they should be used, if at all. For anything, understand the theory, and then it can be correctly applied, often with assistance. Learn methods of application with no understanding, and they will be misapplied, and it also gets harder to achieve the understanding. -- This address is for information only. I do not claim that these views are those of the Statistics Department or of Purdue University. Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399 [EMAIL PROTECTED] Phone: (765)494-6054 FAX: (765)494-0558 = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Evaluating students
In article <[EMAIL PROTECTED]>, Dennis Roberts <[EMAIL PROTECTED]> wrote: >At 08:56 AM 11/16/01 -0700, Roy St Laurent wrote: >>It's not clear to me whether recent posters are serious about these >>examples, but >>I will reiterate my previous post: >>For most mathematics / statistics examinations, the "answer" to a >>question is the >>*process* by which the student obtains the incidental final number or >>result. >>The result itself is most often just not that important to evaluating >>students' >>understanding or knowledge of the subject. And therefore an unsupported >>or lucky answer is worth nothing. >the problems with the above are twofold: >1. this assumes that correct answers are NOT important ... (which believe >me if you are getting change from a cashier, etc. etc. ... ARE ... we just >cannot say that knowing the process but not being able to come up with a >correct answer ... = good performance) >2. that answers without any OTHER supplied information on the part of the >examinee can't be taken as "knowledge" when, it (sometimes) can be >what if you asked on an exam ... the following: >1. what is the mean of 10, 9, 8, 8 and 7? _ >2. what is the mean of 27, 23, 19, 17 and 16? >3. what is the mean of 332, 234, 198, 239, and 200? _ >4. what is the mean of 23.4, 19.8, 23.1, 19.0, and 26.4? _ >and, for each of 1 to 4 ... they put down in the blanks, the correct answers >would you be willing to say that they know how to calculate the mean ... >ie, they know the process that is needed (and can implement it)? What is achieved by asking these questions on an exam? I can see some SIMILAR, but quite different, questions. A good exam, at any level, consists of a few real problems, not the type of answer which a computer program could grind out. >i think you would EVEN though there is no other supporting process >information given by the examinee -- This address is for information only. I do not claim that these views are those of the Statistics Department or of Purdue University. Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399 [EMAIL PROTECTED] Phone: (765)494-6054 FAX: (765)494-0558 = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: biostatistics careers
What _is_ "biostatistics", anyway? A student asked me, and I realized I have only a vague idea. -- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://oakroadsystems.com My reply address is correct as is. The courtesy of providing a correct reply address is more important to me than time spent deleting spam. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: How to write this kind of proposal? any sample?
[cc'd to previous poster; please follow up in newsgroup] Manu Agrawal <[EMAIL PROTECTED]> wrote in sci.stat.edu: >hi; >i have worked out something that can enhance the utility and profits >of Altavista.com. >Can someone please help me on I'll answer a question you didn't ask: talk to a lawyer. Unless you _intend_ to donate your idea to Altavista, you need to make sure it is protected before you present it to them. -- Stan Brown, Oak Road Systems, Cortland County, New York, USA http://oakroadsystems.com My reply address is correct as is. The courtesy of providing a correct reply address is more important to me than time spent deleting spam. = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: F distribution
On 17 Nov 2001, Myles Gartland wrote: > In an F distribution, the critical value for the lower tail is the > reciprocal of the the critical value of the upper tail (with the > degrees of freedom switched). > > Why? I understand how to calculate it, but do not get why the math > works. Essentially for the same reason that in the normal distribution the critical value for the lower tail is the negative of the critical value for the upper tail. Thnke about it. For F = V1/V2, where V1 and V2 are two variance estimates with numbers of degrees of freedom n1 and n2 respectively, the relevant F distribution is said to have "n1 and n2 degrees of freedom", naming the numerator first and then the denominator. For F = V2/V1, the relevant F distribution has n2 and n1 d.f. (hence the interchange of the numbers of degrees of freedom to which you allude). Notice that V2/V1 is the reciprocal of V1/V2. If V1/V2 is sufficiently larger than 1 that the hypothesis of equal variances in the populations can be rejected, then V2/V1 must be sufficiently smaller than 1 to permit rejection. Hence the critical value for V2/V1 must be the reciprocal of the critical value for V1/V2, and the d.f. are interchanged simply by the choice of which direction to divide. Donald F. Burrill [EMAIL PROTECTED] 184 Nashua Road, Bedford, NH 03110 603-471-7128 = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
