literature on convenience sampling
- Forwarded message from Susanne Muigg - now I'm about to finish my thesis, but still looking for some literature about the advantages and disadvantages of a (student) convenience sample, which I had used. Unfortunately, I couldn't find anything, even if I've done quite an extensive literature search in all big Austrian university libraries, in international databanks and via Internet. - End of forwarded message from Susanne Muigg - There are NO STATISTICAL advantages and hence no statistical literature. We try to take random samples because then the laws of probability can be applied to get confidence intervals and hypothesis tests. If you don't take random samples, there is no reason to think those techniques apply, or at least considerable question as to what they mean (if anything). But since convenience is not a mathematical concept, there is no theory, and hence no formulas, and no statistical literature, on what happens when you take convenience samples. The safe approach is to just describe your sample as if it were the population of interest, and confine comments about broader groups to verbal speculation. If that is too bald for your committee, you may need to indulge in some creative obfuscation, but again -- no STATISTICAL literature on that topic either!-) _ | |Robert W. Hayden | | Work: Department of Mathematics / |Plymouth State College MSC#29 | |Plymouth, New Hampshire 03264 USA | * |fax (603) 535-2943 /| Home: 82 River Street (use this in the summer) | )Ashland, NH 03217 L_/(603) 968-9914 (use this year-round) Map of New[EMAIL PROTECTED] (works year-round) Hampshire http://mathpc04.plymouth.edu (works year-round) === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: literature on convenience sampling
Susanne Muigg wrote: Hi there, now I'm about to finish my thesis, but still looking for some literature about the advantages and disadvantages of a (student) convenience sample, which I had used. Unfortunately, I couldn't find anything, even if I've done quite an extensive literature search in all big Austrian university libraries, in international databanks and via Internet. If you know where I could find something about the pros and cons of convenience sampling, please help me! I'm not quite sure I understand what you mean by "convenience sampling". There was a large debate back around the 1920s regarding which was a better method, random sampling or purposive sampling. This debate was decided to have a clear winner: random sampling, and so, you will probably not find much in the recent literature on anything other than random sampling. The only reference I could find in the Encyclopedia of Statistical Sciences to non-random sampling was to an article which I don't have access to, but I provide this reference to you in the hopes that it might help. Smith, T.M.F. (1976) J. R. Statist. Soc. A, 139, 183-204. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] "It's nothing until I call it!" -- Bill Klem, NL Umpire "Those black-eyed peas tasted all right to me" -- Dixie Chicks === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: freeware for DOEs?
If you can do your analyses quickly you can also download the Minitab demo from www.minitab.com. It will give you full functionality for 30 days (at which time it will cease to function). If you are a student, you can learn from this and then buy Minitab when you get a job. If you are not a student -- Don't be so cheap! - Buy Minitab -- good software is worth it!! Donald Burrill wrote: On 4 Jul 2000, Brian A Bucher wrote: Is there a freeware (or cheap, $200) software package that can setup and analyze factorial designs and do response surface analyses? I looked at the "R" software and I couldn't find references to factorial designs or response surface anywhere. Doesn't MIT have a reasonable collection of statistical packages? Probably with site licenses, so it wouldn't cost anything to a member of the community (student or faculty). If not, Minitab has inexpensive academic prices (that, I gather, they don't much advertise). For factorial designs, look for "ANOVA" or "Analysis of variance", or "general linear model" (GLM); for response surface analyses, look for "multiple regression". -- DFB. Donald F. Burrill [EMAIL PROTECTED] 348 Hyde Hall, Plymouth State College, [EMAIL PROTECTED] MSC #29, Plymouth, NH 03264 603-535-2597 184 Nashua Road, Bedford, NH 03110 603-471-7128 === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ === === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: freeware for DOEs?
In article 396259e6$0$[EMAIL PROTECTED], [EMAIL PROTECTED] says... Is there a freeware (or cheap, $200) software package that can setup and analyze factorial designs and do response surface analyses? I looked at the "R" software and I couldn't find references to factorial designs or response surface anywhere. Do you have the pdf-file "Data Analysis and Graphics Using R An Introduction" by J H Maindonald? It's available at Cran sites under "Contributed documentation" or at http://room.anu.edu.au/~johnm. It's a good document to get you started in R and it has information on using contrasts and interactions in R. Good luck, John Hendrickx === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
normal distribution table online for download??
Trying to use in finacial calcs. Hardcosed one to four decimals. Prefer more precision.Thanks. [EMAIL PROTECTED] === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: normal distribution table online for download??
If you think you need more precision than given in the usual tables or with a caculator, think again. You are probably fooling yourself since no distribution in the real world is _exactly_ normal. Jon Cryer At 03:55 PM 7/5/00 GMT, you wrote: Trying to use in finacial calcs. Hardcosed one to four decimals. Prefer more precision.Thanks. [EMAIL PROTECTED] === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ === _ - | \ Jon Cryer[EMAIL PROTECTED] ( ) Department of Statistics http://www.stat.uiowa.edu\ \_ University and Actuarial Science office 319-335-0819 \ * \ of Iowa The University of Iowa dept. 319-335-0706\ / Hawkeyes Iowa City, IA 52242FAX319-335-3017 | ) - V === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: normal distribution table online for download??
bet you can find something here ... http://members.aol.com/johnp71/javastat.html At 03:55 PM 7/5/00 +, MRFCLANCY wrote: Trying to use in finacial calcs. Hardcosed one to four decimals. Prefer more precision.Thanks. [EMAIL PROTECTED] === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ === == Dennis Roberts, EdPsy, Penn State University 208 Cedar Bldg., University Park PA 16802 Email: [EMAIL PROTECTED], AC 814-863-2401, FAX 814-863-1002 WWW: http://roberts.ed.psu.edu/users/droberts/drober~1.htm === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: literature on convenience sampling
I wrote: This doesn't ring true. I ran "convenience sample" (with quotation marks) through http://www.northerlight.com and was greeted with 3,074 items. I didn't read them, but the summaries of the first few items seemed quite relevant to your query. shuda writ http://www.northernlight.com === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: normal distribution table online for download??
We offer six decimals at http://www.stat.ucla.edu/calculators/cdf but also the density, the quantile function, graphs of all these, plus sets of random numbers emailed to you. And this for the most common 20 distributions, including the noncentral ones. At 14:05 -0400 07/05/2000, dennis roberts wrote: bet you can find something here ... http://members.aol.com/johnp71/javastat.html At 03:55 PM 7/5/00 +, MRFCLANCY wrote: Trying to use in finacial calcs. Hardcosed one to four decimals. Prefer more precision.Thanks. [EMAIL PROTECTED] -- === Jan de Leeuw; Professor and Chair, UCLA Department of Statistics; US mail: 8142 Math Sciences Bldg, Box 951554, Los Angeles, CA 90095-1554 phone (310)-825-9550; fax (310)-206-5658; email: [EMAIL PROTECTED] http://www.stat.ucla.edu/~deleeuw and http://home1.gte.net/datamine/ No matter where you go, there you are. --- Buckaroo Banzai http://webdev.stat.ucla.edu/sounds/nomatter.au === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Re: literature on convenience sampling
At 05:46 PM 7/5/00 +, Jerry Dallal wrote: I've been following the thread and I feel I should add that the overall tone of the responses is might be tempered a bit. I'm torn. This is .edu and I'd hate to give students the idea convenience samples are fine. They are not and the reasons are detailed in this thread and the WWW links provided. OTOH, a lot of valuable work has been done on convenience samples. jerry is right of course ... lots can be learned about the people/objects IN the sample ... even if it is a convenient one ... for example ... i might pose a question: i wonder what graduate students think about whether it is feasible to do/take a doctoral program totally online ... ie, can this be done? now, i go into my summer stat class that has in it all (i think) grad students ... ask the question ... and get some responses ... in fact, i might even probe them more deeply about this ... and get what i consider a pretty good idea of what THEY think this could also help me alot in building a survey form that i wanted to administer to a much larger batch of graduate students ... would help me decide which questions i might ask of this larger group ... and which questions i am sort of wasting my time with ... so, in both of the above ... getting information on that 'convenience' sample can be very helpful as long as this as far as i go ... then, this is all it can really help me with ... for, if the question were: i wonder what the typical view is in the overall population of graduate students (or what proportion think it can be done) ... or even graduate students at penn state ... these data are essentially non helpful ... for, whether all of the students in my class mentioned the same thing ... or never mentioned any particular thing ... this does not really tell me anything of import about the overall population ... it is the inference where the problem lies ... and what we can say about the population FROM the sample ... that is of concern ... == Dennis Roberts, EdPsy, Penn State University 208 Cedar Bldg., University Park PA 16802 Email: [EMAIL PROTECTED], AC 814-863-2401, FAX 814-863-1002 WWW: http://roberts.ed.psu.edu/users/droberts/drober~1.htm === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
'Components of chi square'
Hi to all, For some years I have been teaching a technique which I know as testing the components of chi square in a standard contingency table problem. If you calculate the standardised residual SR = (fo - fe)/sqrt(fe) for each cell, these residuals are approximately normally distributed with mean zero and standard error given by SE = sqrt((1 - rowsum/overallsum)*(1-columnsum/overallsum)) provided the expected frequencies are large enough (as for the use of chi square itself). My problem is that I have no source for this technique. I have never seen it in a textbook. (I have no doubt about its validity, and frankly don't understand why textbooks do not refer to it.) Can anyone give me a reference to it? Ideally, a reference to its original publication. My thanks in advance. Alan -- Alan McLean ([EMAIL PROTECTED]) Department of Econometrics and Business Statistics Monash University, Caulfield Campus, Melbourne Tel: +61 03 9903 2102Fax: +61 03 9903 2007 === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
Density Function in Minitab
Friends: How Minitab can show the Density Function of a variable? Can the program calculate this one and show the formula? Thanks Olympio Sent via Deja.com http://www.deja.com/ Before you buy. === This list is open to everyone. Occasionally, less thoughtful people send inappropriate messages. Please DO NOT COMPLAIN TO THE POSTMASTER about these messages because the postmaster has no way of controlling them, and excessive complaints will result in termination of the list. For information about this list, including information about the problem of inappropriate messages and information about how to unsubscribe, please see the web page at http://jse.stat.ncsu.edu/ ===
