Mark Twain
(1835~1910)
There are three kinds of lies.
1. Lies
2. Damned lies
3.Statistics
There are three kinds of lies.
1. Lies
2. Damned lies
3.Statistics
Understand,
“No statistic is perfect.”
People use statistics to persuade us.
How Statistics Are Misused
•Graph
•Bad samples
•Correlation vs. Causality
•Missing data/Error in data
roller-coaster club?
inactive club?
semestervacation
more stable?It can be. But, only one year
sample.
Correlation and Causality
•Arizona is the highest ranked state in respiratory disease death rate.
Estimation: It is because of air pollution in Arizona.
Fact: Many respiratory patients have immigrated to Arizona, which is one of the cleanest states.
About Statistics
naive
critical
cynical
Statistics?
•Who
•Why
•Where
•When
•What
•How
Think critically about
statistics.
Correlation does not imply causality.
•The more firemen fighting a fire, the bigger the fire is observed to be.
Therefore firemen cause an increase in the size of a fire. (x)
Average is not sufficient
•Average Salary
- Company A: $200,000 (100 employees)
- Company B: $150,000 (100 employees)
CEO 99 others
A$10.1 million
$100,000
B$2.13 million
$130,000
•As ice cream sales increase, the rate of drowning deaths increases sharply.
Therefore, ice cream consumption causes drowning. (x)
Correlation does not imply causality.
eyemout
hnose
chin
nose
nose
old woman
eyebrow
mouth
nose
chin
nose
nose
young girl
ear