April 2010
Supporting the Talk: Statistics
Statistics describe the scope of a situation in a compressed space;
but statistics are often misused. My
January 2002 column gives guidelines to consider when using
statistics. Some people misunderstand just what statistics are. They are
not merely numbers or facts or figures—although all three are useful
when giving statistical proof. Statistics can be classed according to
the three major functions they perform: magnitudes, segments, and
trends.
Magnitudes.
A
teacher explaining one million gallons of water was used to extinguish a
fire makes her point this way: “If you use 20 gallons of water to take a
bath; that would be enough water to take 50 thousand baths. You would
have to take one bath each day for 135 years to use a million gallons of
water. Or look at it this way: that much water would fill a swimming
pool 267 feet long, 50 feet wide and 10 feet deep.”
Segments.
Statistics can help listeners understanding by isolating
parts of a problem or issue. A United Way campaign worker wanting to
dispel the notion that people with lower incomes give proportionately
less than those with higher incomes said, “Our surveys show those
earning 25,000 to 50,000 gave approximately 1 per cent of their income.
Those earning 50,000 to 75,000 gave slightly less. Those earning 75,000
to 125,000 gave slightly over 1 percent. In other words, people at
different incomes all give in about the same proportion—an average gift
of 1 percent of their income.”
Trends.
Statistics are useful for describing trends over time. In addressing the
problem of obesity in the United States, a speaker said, “In 1988, no
states reported more than 20% of their population being obese. Ten years
later, 32 states reported that more than 20% of their population was
obese. In 2008, 49 of the 50 states reported that over 20% of their
population was obese. As we can see, obesity is a serious problem in
America.”
So
consider what the functions statistics perform, and then look again at
the guidelines given in the January 2002
column. Wisely used, statistics are powerful supporting material.
