"How To Lie With Statistics" Chapter 10Presentation Transcript
by : David K
Watch out for bias
The presenter may look towards a selection of
favorable data in an act to hide the data that
really doesn’t support his or her conclusion.
Who says so? Many times we hear a study from
universities, scientific laboratories, medical
professional; should we believe it? Please note
that while the data may have come from “Cornell”
the conclusion is entirely dependent on the
writer. So yes the study my be true but what the
presenter wants to come across may be
emphasized instead and therefor bias.
You need to ask yourself if the sample is
large enough to permit any reliable
What information has been omitted prior to being
presented to you? Are you given all of the facts?
Sometimes very valuable numbers are missing.
In example: It is much better to have solid
numbers brought forward instead of a
percentage or an average.
Watch out for a switch between the original
statement and the concluding statement.
For example; “more reported cases of a
disease” is not always the same thing as
“more cases of the disease”.
Make sure it is a study based on actual facts
instead of based upon assumptions or word
It is important to remember one thing, the
trend-to-now may be a fact but the future
trend is no more than an educated guess.
For example: The number of television sets
in American homes increased around 10,000
percent from 1947 to 1952. Project this for
the next five years soon we will have 40 sets
per family. It is like saying you can prove that
soon every family will have 40,000 sets.