Jul 16

The pearls of AP Statistics 8

The stem-and-leaf plot is an archaism - it's time to leave it behind

They say: Another type of graph, called a stem-and-leaf plot, is similar to the dot plot in that it displays individual observations. (Agresti and Franklin, p.33)

I say: The stem-and-leaf plot was invented when computers were not available.

  1. Visually it is inferior to modern ways of representing data
  2. It's drudgery to go from data to the plot and back
  3. It's impossible to use with large samples
  4. No professional statistician uses it
  5. It takes a lot of precious class time

stem and leaf plotThank the guys from The College Board who impose on everybody this outdated and clumsy tool. Another big problem with AP Statistics is its coverage. In one semester the students are supposed to study almost as much as in two semesters of Statistics 1 and Statistics 2 in our program! Of course, we do it with all the algebra, but removing algebra only makes the course enigmatic.

On a related note, Economics is full of jargon introduced by Paul Samuelson in the 1940's to explain the key economic notions to government officials. The problem with those officials was that they did not know much about math, while mathematical notions permeate Economics. Marginal cost and marginal revenue are just derivatives of the cost and revenue functions, and usefulness of using "marginal" names when students are familiar with derivatives is doubtful.

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