Misuse of Statistics: As we will see in the next 12 weeks, statistics when used correctly can be a very powerful tool in managerial decision making.
Statistical techniques are used extensively by marketing, accounting, quality control, consumers, professional sports people, hospital administrators, educators, politicians, physicians, etc…
As such a strong tool, statistics is often misused. Everyone has heard the joke (?) about the statistician who drowned in a river with an average depth of 3 feet or the person who boarded a plane with a bomb because “the odds of two bombs on the same plane are lower than one in one millionth”.
Can you find examples in the popular press of misuse of statistics?
How to Display Data Badly : Read the article “How to Display Data Badly” by Howard Wainer. It is attached here: How to Display Data Badly and also posted under the Content tab (after you choose the Content tab, choose Course Content and Session 1 from the list on the left).
Next read, Chart Junk Considered Useful after All, by Robert Kosara, https://eagereyes.org/criticism/chart-junk-considered-useful-after-all
In your own words, describe “Chart Junk”.
When should Chart Junk be avoided. When is it useful?
Include an image or link to an example of the worst data display you have seen at work or in the media (not in Wainer’s article).
Wainer gives rules for how to make bad charts & graphs. Which of Wainer’s rules describes what’s so bad about your example?
Discussion: Simpson’s Paradox : A family member can go to one of two local hospitals for heart surgery.
Checking the history for the past year, you find that each of the two hospitals has performed cardiac surgery on 1000 patients. In hospital A 710 patients survived (71%). In hospital B 540 (54%) survived.
Based on the numbers presented, which hospital do you think is superior in cardiac surgery?
Surely hospital A is better, right?
Now, let’s look at more data. The below chart summarizes three categories of patients (those entering in fair, serious and critical condition) and the survival rate from surgery (in percent) for the two local hospitals.