[New Quizzes] Add equally weighted partial credit grading to the New Quizzes Multiple Answer question type

[KipHaggerty]

Problem statement:

Current method of partial credit in the New Quizzes (Right - Wrong) * points/(Num of right answers) is not useful for many types of problems that the Multiple Answers problem type should support.

It doesn't work for the following example uses of Multiple Answers:

1. Multiple T/F statements where selecting means true or correct and not selecting means false of incorrect.
2. Binary array answers where selecting means one and not selecting means zero (e.g. edge detection or thresholding images to result in binary images)

Proposed solution:

For the problem examples above, a partial credit scheme that awards partial credit as (Num of correct selected items + Num of correct Not selected items) * points / (Num of checkboxes) provides an equally weighted grading scheme the equally rewards correctly selecting True or One checkboxes and correctly not selecting False or Zero checkboxes.

Proposal: Implement one of the 2 possible solutions listed.

• Solution 1: Add this equally weighted partial credit scheme as an option for the New Quizzes Multiple Answer question.
• Solution 2: Add a new question type to offer similar functionality to multiple answers, but with equally weighted partial credit and name it something like "Multiple Selections," Multiple Checkboxes," or "Multiple T/F."

User role(s):

instructor