Regents Recap — June, 2017: More Trouble With Statistics
High school math courses contain more statistics than ever, which means more statistics questions on end-of-year exams. Sometimes these questions make me wonder what test makers think we are supposed to be teaching. Here are two examples from the June, 2017 exams.
This question puzzled me. The only unambiguous answer choice is (3), which can be quickly eliminated. The other answer choices all involve descriptors that are not clearly defined: “evenly spread”, “skewed”, and “outlier”.
The correct answer is (4). I agree that “79 is an outlier” is the best available answer, but it’s curious that the exam writers pointed out that an outlier would affect the standard deviation of a set of data. Of course, every piece of data affects the standard deviation of a data set, not just outliers.
From the Common Core Algebra 2 exam, here is an excerpt from number 35, a question about simulation, inference, and confidence intervals.
I can’t say I understand the vision for statistics in New York’s Algebra 2 course, but I know one thing we definitely don’t want to do is propagate dangerous misunderstandings like “A 95% confidence interval means we are 95% confident of our results”. We must expect better from our exams.