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QA on “The behavior of tutoring systems”. CPI 494 Feb 3, 2009 Kurt VanLehn. What’s a “task domain”?. Solving linear algebraic equations? Solving 2x+3=5? Solving math problems? Reciting the Gettysburgh Address? Painting color-by-numbers picture? Dancing the Macrarena ? Folk dancing.
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QA on “The behavior of tutoring systems” CPI 494 Feb 3, 2009 Kurt VanLehn
What’s a “task domain”? • Solving linear algebraic equations? • Solving 2x+3=5? • Solving math problems? • Reciting the Gettysburgh Address? • Painting color-by-numbers picture? • Dancing the Macrarena? • Folk dancing. • Writing a funny TV sit-com script
What’s a “task”? • Writing a hiaku on death of a loved one? • Solving 2x+3=5? • Writing the digit 5? • Reading • Reading an electronic schematic for a 2-transitor amplifier.
What is a “step”? • What are the steps in • Solving 2x+5=11? 2x=11-5 2x=6 2x/2=6/2 • Writing the digit “4” • Dividing 10 by 2? • Phonic spelling of the last name of the current US president? • Writing a hiaku on death of a loved one? • Painting a color-by-numbers picture?
What is a “Knowledge component”? • Definition (hint: Uses “independently”)? • What are choices of granularity in solving 2x+5=11?
How to use transfer to check if KC’s are defined correctly • Use KCs to represent task domain, e.g., multi-column addition (496+307) & subtraction • Determine which KCs must be mastered for one set of tasks, e.g., addition A • Determine which KCs must be mastered for a second set of tasks, e.g., subtraction S • Experiment: • Measure time for group S to master subtraction • Measure time for group AS to master subtraction after mastering addition • Group AS should take less time because some of the subtraction KCs are also addition KCs, and thus have been mastered already. • |S-A| / |S| ≈ time(AS)/time(S) • where |X| is the cardinality of set X • Where S-A is the set difference
What is a learning event? • Definition? • Give example from algebra • Give example from teaching your mom how to enter a phone number into her cell phone.
Fourth Third Second First Fifth While studying an example, tries to self-explain; fails; looks in text; succeeds 25 sec. While solving a problem, looks up example; recalls explanation; maps it to problem 20 sec. Recalls explanation; slips; corrects Duration of the instructional event 15 sec. Solves without slips 10 sec. 5 sec. Chronological position of the learning event
Using learning curves to check KCs • Proper KCs should have smooth learning curves Duration of learning event Duration of learning event 1 2 3 4 5 6 7 … 1 2 3 4 5 6 7 … Learning event s in chronological order Learning event s in chronological order
How to collect a learning curve • Track learning of N students • At each of their learning events • Measure time (plot duration on y-axis) • Measure errors (plot error rate on y-axis) • Measure hint requests (plot hints+errors on y-axis) • Aggregate over the N students • E.g., at the 3rd learning event of all N students, count number of students who make error & divide by N plot on y-axis, with x=3.
Two nested loops of an immediate feedback step-based tutoring system • Task (outer) loop: • Select task • Do task • Repeat until student has mastered task domain • Step (inner) loop • Tutor and student do a step, somehow • T:hint; S: trys; T: wrong!; S: trys again; T: Good! • Repeat until the task is finished
What are the 2 loops for CTAT fraction addition tutor? • Outer? • Inner?
Main issue for the task (outer) loop? • How to select the next task? • Where to get tasks to select from?
5 common services for steps • Minimal feedback • Hints on the next step • Error specific feedback • Assessment of knowledge • Review of solution
Main issues for minimal feedback • Correctness? • When?
Main issues for next-step hints • When? • What step to suggest? • How to give hints?
Main issues in error-specific feedback • How to classify errors? • How to give feedback? Debugging… • When/whether to give feedback?
Main issues in assessment • What should be assessed? • Grain size of assessment? • How to measure progress, hints & errors? • How to combine progress, hints & errors?
Main issues in reviewing solutions • Who controls the review? • What depth? • Anything suppressed? • Questions allowed?