Date: Mon, 16 Feb 1998 21:32:44 -0500
To: QandQ@MathCentral.uregina.ca
Subject: graphs

Dana
college student

What exactly is graph distortion? I have to explain it for a project and I can't seem to find anything on it.

Hi Dana

I think that by graph distortion you are referring to what I would call statistical deception or "How to Lie with Statistics".

Here's an example

 Customers in Store C spend less time at the Checkout Counter.

The graph makes it look as if customers in store A spend 4 times as long at the checkout as customers at store C. To get a better representation the graph should be drawn with the vertical axis starting at zero.

Here's another example

 Sales Increase Over Last Year.

Even though the footnote says that the diameters of the circles represent sales we see the area. The 1998 circle has a radius of 1.5 times the radius of the 1997 circle, representing an increase in sales of 50%, but the area of the 1998 circle is 2.25 time the area of the 1997 circle, an increase of 125%.

Cheers,
Penny

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