What is an R. Count in the item analysis?

What is an R. Count in the item analysis?

על ידי Patrick Malley בתאריך
מספר תגובות: 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?
ממוצע דרוגים: -
בתגובה ל: Patrick Malley

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

על ידי Joseph Rézeau בתאריך
תמונה של Core developers תמונה של Particularly helpful Moodlers תמונה של Plugin developers תמונה של Testers תמונה של Translators
Maybe simply R = Right (i.e. total number of students who guessed the answer correctly) ?
בתגובה ל: Joseph Rézeau

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

על ידי Tim Hunt בתאריך
תמונה של Core developers תמונה של Documentation writers תמונה של Particularly helpful Moodlers תמונה של Peer reviewers תמונה של 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?
בתגובה ל: Tim Hunt

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

על ידי Maria B. בתאריך
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



בתגובה ל: Maria B.

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

על ידי Timothy Takemoto בתאריך

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

בתגובה ל: Patrick Malley

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

על ידי Patrick Malley בתאריך
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.