Importance of Statistics
Prerequisites
none
Learning Objectives
 Give examples of statistics are encountered in everyday life
 Give examples of how statistics can lend credibility to an argument
Like most people, you probably feel that it is important
to "take control of your life." But what does this mean?
Partly it means being able to properly evaluate the data and claims
that bombard you every day. If you cannot distinguish good from
faulty reasoning, then you are vulnerable to manipulation and
to decisions that are not in your best interest. Statistics provides
tools that you need in order to react intelligently to information
you hear or read. In this sense, Statistics is one of the most
important things that you can study.
To be more specific, here are some claims that we
have heard on several occasions. (We are not saying that each
one of these claims is true!)
 4 out of 5 dentists recommend Dentyne
 Almost 85% of lung cancers in men and 45% in women are tobaccorelated.
 Condoms are effective 94% of the time.
 Native Americans are significantly more likely to be hit crossing
the streets than are people of other ethnicities.
 People tend to be more persuasive when they look others directly
in the eye and speak loudly and quickly.
 Women make 75 cents to every dollar a man makes when they
work the same job.
 A surprising new study shows that eating egg whites can increase
one's life span.
 People predict that it is very unlikely there will ever be
another baseball player with a batting average over 400.
 There is an 80% chance that in a room full of 30 people that
at least two people will share the same birthday.
 79.48% of all statistics are made up on the spot.
All of these claims are statistical in character. We suspect that
some of them sound familiar; if not, we bet that you have heard
other claims like them. Notice how diverse the examples are. They
come from psychology, health, law, sports, business, etc. Indeed,
data and datainterpretation show up in discourse from virtually
every facet of contemporary life.
Statistics are often presented in an effort to add
credibility to an argument or advice. You can see this by paying
attention to television advertisements. Many of the numbers thrown
about in this way do not represent careful statistical analysis.
They can be misleading, and push you into decisions that you might
find cause to regret.
For these reasons, learning about statistics is a long step towards
taking control of your life. (It is not, of course, the only step
needed for this purpose.) The present online textbook is designed
to help you learn statistical essentials. It
will make you into an intelligent consumer of statistical claims.
You can take the first step right away. To be an intelligent
consumer of statistics, your first reflex must be to question the statistics that you encounter. The British
Prime Minister Benjamin Disraeli famously said, "There are
three kinds of lies  lies, damned lies, and statistics."
This quote reminds us why it is so important to understand statistics.
So let us invite you to reform your statistical habits from
now on. No longer will you blindly accept numbers or findings.
Instead, you will begin to think about the numbers, their sources,
and most importantly, the procedures used to generate them.
We have put the emphasis on defending ourselves against
fraudulent claims wrapped up as statistics. We close this section
on a more positive note. Just as important as detecting the deceptive
use of statistics is the appreciation of the proper use of statistics.
You must also learn to recognize statistical evidence that supports
a stated conclusion. Statistics are all around you, sometimes
used well, sometimes not. We must learn how to distinguish the
two cases.
Now let us get to work!
