RE:[tips] Teaching stats and Critical Values Tables
On: Sat, 8 Apr 2017 00:42:52 +, , Lenore Frigo wrote: For those of you who teach lower-division introduction to research methods (or have an opinion on what we SHOULD be teaching at that level): In teaching students how to interpret statistical results, such as a t-test, do you think it's important to have them find the critical value on a table and proceed from there, or just start with a "print out" of the results that would already include the actual p value? Though not immediately obviously, the question you ask turns out to be far more complex because of a variety of factors. I try to identify some of these in the points below: (1) The information that you have provicded does not make clear whether you students understand the concept of a sampling distribution of a statistics and why one is looking to determine whether the value of an obtained statistic is is consistent or not with the null hypothesis. Presumably, in the case of the t-test you are mostly concerned with rejecting the null hypothesis (in contrast to situations where you are doing a variation of goodnees of fit between, say, some criterion value and your obtained value, for example comparing the mean IQ of a sample to a value of 100 [the value of the population mean]). If you teach the goodness of fit chi-square for a frequency distribution, the emphasis is on NOT rejecting the null (which might claim that sample frequency distribution is consistent with a normal distribution). (2) There are phiilosophical (metaphysical?) issues involves as well depending upon whether one considers oneself to be either a Fisherian/Neofisherian when it comes to statistical inference or one subscribes to the model promoted by the Neyman-Pearson approach (which includes concepts such as Type II errors, statistical power, and so on). As Gerd Gigerenzer argued so long ago, most psychologist were taught a mash-up of these two inference frameworks which has resulted in neither being used corrested. With respect to the use of a table of "critical value" or probabilities (p-values), the position that one subscribes partlyy determines what one does. Consider the following situation: (a) A researcher that take a Fisherian approach to statistical testing will conduct their research and after the data is in, analyze it to determine whether test results are either consistent with the null hypothesis (e.g., p(obtain test value) > .05) or inconsistent with it (i.e., p(obtained test value) < .05). Here a table or some other source of critical test values or the probability of the of the obtained test rest if the null hypothesis is true plays a critical role because one is in essence just deciding whether the obtained value should lead one to reject the null hypothesis or fail to reject it. One might go on to do some additional analyses but the most critical question that one is interested in should have been answered. (b) In the Neyman-Pearson approach, we need to distinguish between whether one is an "a priorist" or a "post hoc" practioner. The distinction between the two is illustrated in the following: (i) The proper way to do a statistical analysis in the Neyman-Pearson framework requires one to identify what population distributions are involved in the null and alternative hypotheses. In addition, if one is going to conduct a two-sample between-subjects experiment (NOTE: the tense implies that all this is done before any data is collected), and one will use an independent groups t-tests as the tool of analysis, there the following consideration or decision one must make: - What is the Type I Error rate that one will use? Typically, we use alpha - .05 but, if we expect to be doing several test, we may wish to use a Bonferroni correction so that the overall Type I error rte is equal to .05 but this means that the individual tests will use an alpha < .05 (examination of a table of Bonferroni t-test values corrected for the number of tests done will identify the relevant critical values but these usually assume that one divides the Type I error equally over each test, so, if one is doing 3 t-tests, the the per comparison alpha will be .05/3 = 0.01667; however, a research can decide to assign a Type I error rate = .02 to two tests and .01 to the third test for whatever reason [researchers do the darnedest things] but I have not seen any tables like this which means that one has to get the critical values either through hand calculation or some software program if one really is going to focus on the value of the test statistic instead of its p-value).. - What is the Effect Size (ES) that one is trying to detect? The ES in the independent groups t-test situation represents the standarding distance between the populations means of the distributions specified in the alternative hypothesis. This difference, represented by delta in the population and d in the sample, is required to figure out other aspects of the test but it also represents what one kn
RE: [tips] Teaching stats and Critical Values Tables
I agree with all these comments. One additional point; I always use the table to point out that as N approaches infinity, the t distribution approaches normality (since I’ve already hammered on z=1.96 for a two-tailed normal distribution cut off of .05). bob k. From: Michael Scoles [mailto:micha...@uca.edu] Sent: Saturday, April 8, 2017 6:32 AM To: Teaching in the Psychological Sciences (TIPS) Subject: Re: [tips] Teaching stats and Critical Values Tables Looking at a table shows them that more conservative decisions require greater evidence, and that the reliability of that evidence is related to sample size (or degrees of freedom). On Fri, Apr 7, 2017 at 10:07 PM, Jim Clark mailto:j.cl...@uwinnipeg.ca>> wrote: Hi I second Stuart's process assuming prior familiarity with hypothesis testing. Understand the distribution. If preceded by normal distribution, generalize from that to distribution that is more spread out because SD is varying as well as numerator; also varies with df. Then use table to determine critical values with associated ps. Finally, p values from printout. Jim -Original Message- From: Stuart McKelvie [mailto:smcke...@ubishops.ca<mailto:smcke...@ubishops.ca>] Sent: 7-Apr-17 9:15 PM To: Teaching in the Psychological Sciences (TIPS) mailto:tips@fsulist.frostburg.edu>> Subject: RE:[tips] Teaching stats and Critical Values Tables Dear Tipsters, My response to Lenore's question is that they must learn to use the table, but that should only be the natural outcome of understanding the distribution of t and how it arises in repeated sampling. So - understanding first, table second and printout third. But of course, after you understand, the printout is all you need. Stuart -Original Message- From: Frigo, Lenore [mailto:lfr...@shastacollege.edu<mailto:lfr...@shastacollege.edu>] Sent: April-07-17 8:43 PM To: Teaching in the Psychological Sciences (TIPS) Subject: [tips] Teaching stats and Critical Values Tables For those of you who teach lower-division introduction to research methods (or have an opinion on what we SHOULD be teaching at that level): In teaching students how to interpret statistical results, such as a t-test, do you think it's important to have them find the critical value on a table and proceed from there, or just start with a "print out" of the results that would already include the actual p value? Currently I have them work with the table, but it seems old-fashioned and unnecessarily cumbersome. On the other hand, using the table forces them to perhaps have a bit more conceptual understanding of what they are doing. All input and opinions most welcome, -Lenore Lenore Frigo lfr...@shastacollege.edu<mailto:lfr...@shastacollege.edu> --- You are currently subscribed to tips as: smcke...@ubishops.ca<mailto:smcke...@ubishops.ca>. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13510.2cc18398df2e6692fffc29a610cb72e3&n=T&l=tips&o=50644 or send a blank email to leave-50644-13510.2cc18398df2e6692fffc29a610cb7...@fsulist.frostburg.edu<mailto:leave-50644-13510.2cc18398df2e6692fffc29a610cb7...@fsulist.frostburg.edu> --- You are currently subscribed to tips as: j.cl...@uwinnipeg.ca<mailto:j.cl...@uwinnipeg.ca>. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=3229968.90f21a83d5f62f052ba84a49e2f91291&n=T&l=tips&o=50645 or send a blank email to leave-50645-3229968.90f21a83d5f62f052ba84a49e2f91...@fsulist.frostburg.edu<mailto:leave-50645-3229968.90f21a83d5f62f052ba84a49e2f91...@fsulist.frostburg.edu> --- You are currently subscribed to tips as: micha...@uca.edu<mailto:micha...@uca.edu>. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=357701.a768e95c4963686e69b47febf8aa657a&n=T&l=tips&o=50646 or send a blank email to leave-50646-357701.a768e95c4963686e69b47febf8aa6...@fsulist.frostburg.edu<mailto:leave-50646-357701.a768e95c4963686e69b47febf8aa6...@fsulist.frostburg.edu> -- Michael T. Scoles, Ph.D. Associate Professor of Psychology & Counseling University of Central Arkansas Conway, AR 72035 501-450-5418 --- You are currently subscribed to tips as: kee...@msmary.edu<mailto:kee...@msmary.edu>. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13318.631e08b59d01b18c9d5477a62647e03b&n=T&l=tips&o=50650 (It may be necessary to cut and paste the above URL if the line is broken) or send a blank email to leave-50650-13318.631e08b59d01b18c9d5477a62647e...@fsulist.frostburg.edu<mailto:leave-50650-13318.631e08b59d01b18c9d5477a62647e...@fsulist.frostburg.edu> --- You are currently subscribed to tips as: arch...@mail-archive.com. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=50652 or send a blank email to leave-50652-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
Re: [tips] Teaching stats and Critical Values Tables
Looking at a table shows them that more conservative decisions require greater evidence, and that the reliability of that evidence is related to sample size (or degrees of freedom). On Fri, Apr 7, 2017 at 10:07 PM, Jim Clark wrote: > Hi > > I second Stuart's process assuming prior familiarity with hypothesis > testing. Understand the distribution. If preceded by normal distribution, > generalize from that to distribution that is more spread out because SD is > varying as well as numerator; also varies with df. Then use table to > determine critical values with associated ps. Finally, p values from > printout. > > Jim > > -Original Message- > From: Stuart McKelvie [mailto:smcke...@ubishops.ca] > Sent: 7-Apr-17 9:15 PM > To: Teaching in the Psychological Sciences (TIPS) < > tips@fsulist.frostburg.edu> > Subject: RE:[tips] Teaching stats and Critical Values Tables > > Dear Tipsters, > > My response to Lenore's question is that they must learn to use the table, > but that should only be the natural outcome of understanding the > distribution of t and how it arises in repeated sampling. > > So - understanding first, table second and printout third. But of course, > after you understand, the printout is all you need. > > Stuart > > > -Original Message- > From: Frigo, Lenore [mailto:lfr...@shastacollege.edu] > Sent: April-07-17 8:43 PM > To: Teaching in the Psychological Sciences (TIPS) > Subject: [tips] Teaching stats and Critical Values Tables > > For those of you who teach lower-division introduction to research methods > (or have an opinion on what we SHOULD be teaching at that level): > > In teaching students how to interpret statistical results, such as a > t-test, do you think it's important to have them find the critical value on > a table and proceed from there, or just start with a "print out" of the > results that would already include the actual p value? > > Currently I have them work with the table, but it seems old-fashioned and > unnecessarily cumbersome. On the other hand, using the table forces them to > perhaps have a bit more conceptual understanding of what they are doing. > > All input and opinions most welcome, > -Lenore > > Lenore Frigo > lfr...@shastacollege.edu > > > --- > You are currently subscribed to tips as: smcke...@ubishops.ca. > To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13510. > 2cc18398df2e6692fffc29a610cb72e3&n=T&l=tips&o=50644 > or send a blank email to leave-50644-13510.2cc18398df2e6692fffc29a610cb72 > e...@fsulist.frostburg.edu > > --- > You are currently subscribed to tips as: j.cl...@uwinnipeg.ca. > To unsubscribe click here: http://fsulist.frostburg.edu/u?id=3229968. > 90f21a83d5f62f052ba84a49e2f91291&n=T&l=tips&o=50645 > or send a blank email to leave-50645-3229968. > 90f21a83d5f62f052ba84a49e2f91...@fsulist.frostburg.edu > > > --- > You are currently subscribed to tips as: micha...@uca.edu. > To unsubscribe click here: http://fsulist.frostburg.edu/u?id=357701. > a768e95c4963686e69b47febf8aa657a&n=T&l=tips&o=50646 > or send a blank email to leave-50646-357701.a768e95c4963686e69b47febf8aa65 > 7...@fsulist.frostburg.edu > -- Michael T. Scoles, Ph.D. Associate Professor of Psychology & Counseling University of Central Arkansas Conway, AR 72035 501-450-5418 --- You are currently subscribed to tips as: arch...@mail-archive.com. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=50650 or send a blank email to leave-50650-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
RE:[tips] Teaching stats and Critical Values Tables
Hi I second Stuart's process assuming prior familiarity with hypothesis testing. Understand the distribution. If preceded by normal distribution, generalize from that to distribution that is more spread out because SD is varying as well as numerator; also varies with df. Then use table to determine critical values with associated ps. Finally, p values from printout. Jim -Original Message- From: Stuart McKelvie [mailto:smcke...@ubishops.ca] Sent: 7-Apr-17 9:15 PM To: Teaching in the Psychological Sciences (TIPS) Subject: RE:[tips] Teaching stats and Critical Values Tables Dear Tipsters, My response to Lenore's question is that they must learn to use the table, but that should only be the natural outcome of understanding the distribution of t and how it arises in repeated sampling. So - understanding first, table second and printout third. But of course, after you understand, the printout is all you need. Stuart -Original Message- From: Frigo, Lenore [mailto:lfr...@shastacollege.edu] Sent: April-07-17 8:43 PM To: Teaching in the Psychological Sciences (TIPS) Subject: [tips] Teaching stats and Critical Values Tables For those of you who teach lower-division introduction to research methods (or have an opinion on what we SHOULD be teaching at that level): In teaching students how to interpret statistical results, such as a t-test, do you think it's important to have them find the critical value on a table and proceed from there, or just start with a "print out" of the results that would already include the actual p value? Currently I have them work with the table, but it seems old-fashioned and unnecessarily cumbersome. On the other hand, using the table forces them to perhaps have a bit more conceptual understanding of what they are doing. All input and opinions most welcome, -Lenore Lenore Frigo lfr...@shastacollege.edu --- You are currently subscribed to tips as: smcke...@ubishops.ca. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13510.2cc18398df2e6692fffc29a610cb72e3&n=T&l=tips&o=50644 or send a blank email to leave-50644-13510.2cc18398df2e6692fffc29a610cb7...@fsulist.frostburg.edu --- You are currently subscribed to tips as: j.cl...@uwinnipeg.ca. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=3229968.90f21a83d5f62f052ba84a49e2f91291&n=T&l=tips&o=50645 or send a blank email to leave-50645-3229968.90f21a83d5f62f052ba84a49e2f91...@fsulist.frostburg.edu --- You are currently subscribed to tips as: arch...@mail-archive.com. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=50646 or send a blank email to leave-50646-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
RE:[tips] Teaching stats and Critical Values Tables
Dear Tipsters, My response to Lenore's question is that they must learn to use the table, but that should only be the natural outcome of understanding the distribution of t and how it arises in repeated sampling. So - understanding first, table second and printout third. But of course, after you understand, the printout is all you need. Stuart -Original Message- From: Frigo, Lenore [mailto:lfr...@shastacollege.edu] Sent: April-07-17 8:43 PM To: Teaching in the Psychological Sciences (TIPS) Subject: [tips] Teaching stats and Critical Values Tables For those of you who teach lower-division introduction to research methods (or have an opinion on what we SHOULD be teaching at that level): In teaching students how to interpret statistical results, such as a t-test, do you think it's important to have them find the critical value on a table and proceed from there, or just start with a "print out" of the results that would already include the actual p value? Currently I have them work with the table, but it seems old-fashioned and unnecessarily cumbersome. On the other hand, using the table forces them to perhaps have a bit more conceptual understanding of what they are doing. All input and opinions most welcome, -Lenore Lenore Frigo lfr...@shastacollege.edu --- You are currently subscribed to tips as: smcke...@ubishops.ca. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13510.2cc18398df2e6692fffc29a610cb72e3&n=T&l=tips&o=50644 or send a blank email to leave-50644-13510.2cc18398df2e6692fffc29a610cb7...@fsulist.frostburg.edu --- You are currently subscribed to tips as: arch...@mail-archive.com. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=50645 or send a blank email to leave-50645-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu