Making use of Rarely Given Wrong Answers on the Force Concept Inventory

1
Making use of Rarely Given Wrong Answers on the
Force Concept Inventory

• A. John Mallinckrodt
• Cal Poly Pomona
• ajm_at_csupomona.edu

2
The Problem

• Many administer the FCI in ungraded, credit for
  completion mode.
• How do we establish that the test has been taken
  in good faith?

3
One Solution

• Have a way to identify exams that are not taken
  in good faith and
• tell the class about it!

4
Rarely Given Wrong Answers

• The FCI has a large number of distractors that
  are rarely chosen by studentsRGWAs
• Random choice leads to an anomalously high
  occurrence frequency for RGWAs

5
Defining RGWAs

• Choice of database
• Large set of previous results
• Current cohort
• Choice of frequency(My discriminator 1/f
  minimum number of exams expected to yield one
  instance of the specific RGWA)

6
Procedure

• Collect frequencies for all answers
• Decide on a set of RGWAs
• Determine expected number of RGWAs
• For random guessing (Total number of RGWAs/5)
• For good faith effort ( Sum of ps for each
  RGWA)
• Compare with individual results(Note We can
  always expect random guessing to produce 6
  correct answers.)

7
Examples
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Now what?

• To confront or not to confront?
• To deny credit or not to deny credit?

9
Conclusions

• RGWAs seem to provide a relatively robust method
  of identifying bad faith efforts
• Still needed
• Larger databases
• Better statistical analyses
• More user-friendly (user-friendlier?) interface
• Interest from FCI community (?)

10
Making use of Rarely Given Wrong Answers on the
Force Concept Inventory

• A. John Mallinckrodt
• Cal Poly Pomona
• ajm_at_csupomona.edu