Aug 16

The pearls of AP Statistics 9

Your word is gold. Don't be sloppy with definitions and their sequencing: they are the foundation of theory.

They say: Do the data have a single mound? A distribution of such data is called unimodal. The highest point is at the mode. A distribution with two distinct mounds is called bimodal. (Agresti and Franklin,p.39)

I say: Is this supposed to be the definition of the mode? The mode is not defined explicitly, whereas the notions of a unimodal and bimodal distributions derive from it. Later, on p. 57, the mode is said to be the most frequent value; this should have been said in the beginning.

One of the biggest drawbacks of AP Statistics is absence of logical order. Show your students what comes from where.

definitionA definition starts with a preamble which sets a background and allows you to see the existence of objects with distinct properties. Most of the time the preamble is not even mentioned but there are cases when it contains a complex logical argument. After you understand the preamble understanding the definition proper – that is giving the name – becomes easy. Studying a definition is concluded by considering possible equivalent definitions and deriving immediate consequences.

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