This tick box allows you to give quiz takers credit for an answer that is not 100% correct in the sequencing and matching question types.
For matching questions a score based on the number of correct matches is awarded.
For sequencing questions, a more complex scoring method is used by calculating the number of correct relative pairs sequenced. (There's a blog article here that goes into more detail, [1]).
Allow Overall Negative Marks From Partial Credit Questions
You can choose whether or not you allow negative scores for Partial Credit Questions. These negative scores will the be set against positive scores achieved in other questions. If you don't allow negative scores, the minimum score that can be awarded for any question is 0.