Each student is expected to post at least twice. For your original post, please select one topic to work on. Reply to at least one class member’s post. Replies should be meaningful. Avoid responses such as “Great job”, “I agree with you”, etc., that do not add content.
- Descriptive Statistics: In six sentences or more, explain how you would use the descriptive statistical procedure(s) at work or in your personal life.
- 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). For a summary, Wainer Explained.
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.
Patient Entering Condition
Hospital A
Hospital B
Survivors from A (# and percent)
Survivors from B (# and percent)
Fair
700
100
600 or 86%
90 or 90%
Serious
200
200
100 or 50%
150 or 75%
Critical
100
700
10 or 10%
300 or 43%
Total
1000
1000
710 or 71%
540 or 54%
Looking at the data broken down in this way, we see that Hospital B has a higher success rate in all three categories of patients but when averaged all together, Hospital A has the higher overall survival rate. Based on the numbers presented, which hospital do you think is superior in cardiac surgery?
