Final answer:
The missing type of informal assessment strategy in the question likely refers to formative assessment, which includes activities such as practice problems and performance tasks to provide feedback during the learning process.
Step-by-step explanation:
The question seems to be missing information regarding the 'type of informal assessment strategy' it refers to. However, given the context provided about various types of assessments, we can deduce that the most fitting instructional purpose for using informal assessment strategies is likely formative assessment. Formative assessments are designed to monitor student learning and provide ongoing feedback that can be used by instructors to improve their teaching and by students to improve their learning. Strategies for formative assessment include grasp checks, practice problems, and performance tasks. These activities help assess the understanding of concepts and skills during the learning process, rather than at the end, as with summative assessments.
It is important to distinguish formative assessment from summative assessment, norm-referenced assessment, and criterion-referenced assessment. Summative assessments evaluate student learning at the conclusion of an instructional period, norm-referenced assessments compare a student's performance with a group, and criterion-referenced assessments measure student performance against a fixed set of standards or criteria.