If you’re the sort of person who helps students learn to design controlled experiments, you might offer them W. Stephen Wilson’s experiment in The Atlantic and ask for their critique.
First, Wilson’s hypothesis:
Wilson fears that students who depend on technology [calculators, specifically –dm] will fail to understand the importance of mathematical algorithms.
Next, Wilson’s experiment:
Wilson says he has some evidence for his claims. He gave his Calculus 3 college students a 10-question calculator-free arithmetic test (can you multiply 5.78 by 0.39 without pulling out your smartphone?) and divided the them into two groups: those who scored an eight or above on the test and those who didn’t. By the end of the course, Wilson compared the two groups with their performance on the final exam. Most students who scored in the top 25th percentile on the final also received an eight or above on the arithmetic test. Students at the bottom 25th percentile were twice as likely to score less than eight points on the arithmetic test, demonstrating much weaker computation skills when compared to other quartiles.
I trust my readers will supply the answer key in the comments.
BTW. I’m not saying there isn’t evidence that calculator use will inhibit a student’s understanding of mathematical algorithms, or that no such evidence will ever be found. I’m just saying this study isn’t that evidence.
@ddmeyer I think you just found me a new example for chapter 4 (experimental design)...— David Griswold (@DavidGriswoldHH) December 23, 2016
The most clarifying thing that I can recall being told about testing in mathematics came from a friend in that business: you’ll find a positive correlation between student performance on almost any two math tests. So don’t get too excited when it happens, and beware of using evidence of correlation on two tests as evidence for much.