文档介绍：统计学的成功案例和警示故事
最早的英文原版《打败庄家》
SEVEN STATISTICAL STORIES WITH MORALS
7个包含寓义的统计学故事
There are three kinds of lieartiles
89
110
Median
Females
(102 Students)
Males
(87 Students)
Simple summaries of data can tell an interesting story and are easier to digest than long lists.
CASE STUDY 2
Disaster in the Skies?
空中的灾难？
“Planes get closer in midair as traffic control errors rise.
Errors by air traffic controllers climbed from 746 in fiscal 1997 to 878 in fiscal 1998, an 18% increase”
-USA TODAY, Levin, 1999
“The errors per million flights handled by controllers climbed from to ”
=%
Definition: The rate is simply the number of times something occurs per number of opportunities for it to occur. Baseline rate is the rate at a beginning time period or under specific conditions.
Moral of the story
When discussing the change in the rate or risk of occurrence of something, make sure you also include the base rate or baseline risk.
CASE STUDY 3
Did anyone ask you whom you’ve been dating?
“According to a new USA Today/Gallup Poll of teenagers across the country, 57 percent of teens who go out on dates say they’ve been out with someone of another race or ethnic group.”
-USA TODAY, Perterson, 1997
CASE STUDY 3
“In most cases, parents aren’t a major obstacle. Sixty-four percent of teens says their parents don’t mind that they date interracially, or wouldn’t mind if they did.”
-Sacramento Bee, Hiram , 1997
How could the polltakers manage to ask so many teenagers these question?
Question 1
Could such a small sample possibly tell us anything about the millions of teenagers in the United States ?
Question 2
Yes
-if those teens constituted a random sample from the population of interest.
How accurate could this sample possibly be ?
Question 3
The results of this poll are accurate to within a margin of error of about % (95% confidence interval).
Moral of the story
A representative sample of only a few thousand, or p