Chapter 3 and Sec. 2.6
The purpose of statistics is to gain understanding from the world around us by
This is NOT a math class.
We will use some mathematical tools, but memorizing formulas is
not the focus.
This is a critical thinking class.
My goal is to give you some statistical tools and
principles that will help you critically view and analyze the immense amount of data, studies,
articles etc. that you encounter daily.
This course is divided into 2 parts:
Gathering and working with data (graphing, summarizing, designing studies to gather data).
Establishing relationships and drawing conclusions from the data (statistical inference).
Statistics can be informative and can help us to make educated decisions.
However, not every
use of statistics in the media, politics, or our culture is legitimate.
Rural vs. urban roads example:
“A country drive might be relaxing, but it can also be
Forty-two percent more fatal crashes occur in rural parts of the country than on
busy stretches of highways through cities and suburbs, the National Highway Traffic Safety
Administration said Thursday.
Focusing on fatal crashes from 1994 through 2003, the study
found rural crashes are more likely to involve multiple fatalities, rollovers, and motorists being
thrown from the vehicles.
Making matters worse, it takes longer for emergency medical
services to arrive at the scene…In 2003, Montana led the nation with 95.4% of its fatal crashes
occurring along rural roads, followed by Maine, South Dakota, and South Carolina.
Island had the lowest rate with 17.7% of traffic fatalities on rural roads, followed by
Massachusetts, Connecticut, and New Jersey.”
Suppose you want data on a question of interest to you.
Does chronic lack of
sleep affect weight gain?
(from a Journal and Courier
article on December 21, 2004)
What is the best approach to finding the data?
It is easy to simply answer our questions based
on a few observations.
In this case, however we are relying on anecdotes rather than data.
“My friend’s aunt said…………….
is based on haphazardly selected individual cases which often come to our
attention because they are striking in some way.
These cases need not be representative of
any larger group of cases. (“News of the Weird” or a “Dateline” lead story)
These cases need
not be representative of any larger group of cases.
Anecdotal evidence is NOT good science!
STAT 301 Spring 2012