What is an R. Count in the item analysis?

What is an R. Count in the item analysis?

od Patrick Malley -
Število odgovorov: 5
I know what the function of an R. Count is - to count the total number of students who guess a particular answer.  But, what is "R"? 

This is probably something simple or statistical that I am missing?  Is it ratio?
Povprečje ocenitev: -
V odgovor na Patrick Malley

Re: What is an R. Count in the item analysis?

od Joseph Rézeau -
Slika Core developers Slika Particularly helpful Moodlers Slika Plugin developers Slika Testers Slika Translators
Maybe simply R = Right (i.e. total number of students who guessed the answer correctly) ?
V odgovor na Joseph Rézeau

Re: What is an R. Count in the item analysis?

od Tim Hunt -
Slika Core developers Slika Documentation writers Slika Particularly helpful Moodlers Slika Peer reviewers Slika Plugin developers
I have not worked this out yet. Looking at the quiz reports is pencilled into my personal roadmap for between October and December.

It may be some sort of regression co-efficient. Other quiz analysis systems use a statistic that is basically "is there a good correlation between the students' score on this question, and their score on the whole quiz?" If there is a good correlation, then that question is probably a good indicator of ability.

By the way, have you tried clickin on the help buttons or looking in MoodleDocs?
V odgovor na Tim Hunt

Re: What is an R. Count in the item analysis?

od Maria B. -
Good indicator of reliability is "image" - squared multiple correlations between each variable and all other variables.

Discrimination Coefficient means Corrected Item-Total Correlation or not?

DC = Sum(xy)/ (N * sx * sy)

Some statistical packages, like SPSS, use overall quiz scores decremented by score for that particular queastion i.e. C = Y - X



V odgovor na Maria B.

Re: What is an R. Count in the item analysis?

od Timothy Takemoto -

I don't think it is corrected. It does not mention that in the documentation.

When all the students get a question correct, and so I guess that the discrimination coefficient should be 0 (zero) because it has no power of discrimination but it is also not reverse discriminating, but in moodle 1.53 it is calculated to be 999.

Tim

V odgovor na Patrick Malley

Re: What is an R. Count in the item analysis?

od Patrick Malley -
I'll reply to myself with a possible answer here.

Someone in a training session I was conducting at my school said "Raw."

Whether this is correct or not, I'm not sure. But, it works. "Raw Count." "Raw %."

Thought I should share.