Thanks Angus. I think I almost understood your point and your blog post, but... (and
I think this will make your teeth grind...!) that level of detail, honestly, frankly,
doesn't really matter for my students. They're undergrad sociolinguists, and
demonstrating any awareness of statistics is a huge (significant!) leap from the
kinds of impressionistic treatment they would otherwise fall back on. As you
indicate, these problems pervade grad schools and journals, so it's the kind of thing
I can let slide in second year undergrads.
As for my analysis of grades, I'm not really sure I understood that part of your
concern. I'm running the test on all the grades that have been moderated, and the
sample that goes for moderation is selected at random from each grade boundary. The
conclusion of your concern is that the grades need to be sampled differently (fine)
or that more papers need to be moderated (not fine!). How do you go about moderation?
I'm very much open to suggestions for improvement.
Thanks,
Dave
--
Dr. Dave Sayers
Senior Lecturer, Dept Humanities, Sheffield Hallam University | www.shu.ac.uk
Honorary Research Fellow, Cardiff University & WISERD | www.wiserd.ac.uk
[log in to unmask] | http://shu.academia.edu/DaveSayers
On 26/01/2016 19:34, Angus B. Grieve-Smith wrote:
> Statistical significance is a good idea, Dave, but before you can push your
> students (and yourself) to test for it you need to get representative samples. If
> the students in your classes are not assigned at random, they are not a
> representative sample of anything.
>
> http://grieve-smith.com/blog/2014/01/you-cant-get-significance-without-a-representative-sample/
>
>
>
> On 1/26/2016 6:11 AM, Dave Sayers wrote:
>> Hi TeachLingers,
>>
>> Having pestered my students for years to test their research data for statistical
>> significance, I suddenly wondered why I'd never interrogated their grades in the
>> same detail! I started today by comparing my grades with the grades of the internal
>> second marker. I just suddenly realised that our decisions over whether a
>> difference in our grades warranted adjustment had so far been a bit unscientific.
>>
>> Running a statistical significance test used to require a fair amount of training
>> (that separated the wheat from the chaff in my A-level biology class!) but nowadays
>> it's really trivially easy with one of a number of free online utilities, e.g.
>> http://graphpad.com/quickcalcs/ttest1.cfm.
>>
>> I'm also thinking that this could be of use for other purposes, e.g. to compare
>> different yearly cohorts to track improvement of a module, or to compare a single
>> student's grades across the years of their degree to track their progress. There
>> are lots of other possibilities I'm sure.
>>
>> Has anyone used statistical analysis on grades before? What were the effects? Were
>> those effects... significant?
>>
>> Dave
>>
>> --
>> Dr. Dave Sayers
>> Senior Lecturer, Dept Humanities, Sheffield Hallam University | www.shu.ac.uk
>> Honorary Research Fellow, Cardiff University & WISERD | www.wiserd.ac.uk
>> [log in to unmask] | http://shu.academia.edu/DaveSayers
>>
>>
>> ---
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