A powerpoint presentation on four types of Misleading Statistics based on Chapter 7 of "Critical Reading", an internal publication by Unindra

1. RECOGNIZING
STATISTICAL SLIPS
Presented by:
Hellaisna N. G
200912570094

2. Statistics is....
• Plural
Statistics is information about any phenomenon or
activity expressed in numerical form, such as
vital statistics, college enrollment figures, and
opinion poll percentages.
• Singular
Statistics is the art & science of collecting,
presenting, analyzing, and interpreting numerical
data.

3. Common Statistical Slips
• The Deceptive Sample
• The Misleading Average
• Plausible Charts and Graphs
• Presenting the Facts without a Reference
Point

4. The Deceptive Sample
 Error in sampling.
Interpretation of statistic output doesn’t
represent true fact of total of population.
 How could this happen:
 Sample bias or too small
 Sample chosen to prove the writer’s point

5. Brand Manager of Head & Shoulders released the statement:
“Head & Shoulders is the best brand for
shampoo category in Indonesia.”
*based on national consumer survey in 2010.
The Questions are:
Are samples chosen by pure random method?
How many samples are surveyed?
Is it enough to represent total of Indonesian
population?

6. The Misleading Average
• Generating a wrong conclusion because the data
didn’t distribute normal.
• Example:
“Indonesia can’t acces a soft loan from the
World Bank because its per capita income is
above average.”

7. So, what’s the big deal??
It is because the World Bank put their
conclusion on per capita income.
But, what about the data?
Does it show a true fact about Indonesia?

8. Income (I) Population (P) Sum of P x I
US$ 100 50 US$ 5.000
US$ 200 150 US$ 30.000
US$ 300 300 US$ 90.000
US$ 400 250 US$ 100.000
US$ 500 200 US$ 100.000
US$ 600 0 US$ 0
US$ 700 0 US$ 0
US$ 800 0 US$ 0
US$ 900 2000 US$ 18.000
US$ 1000 150 US$ 150.000
TOTAL 1.300 US$ 655.000
 Indonesia’s Per Capita Income is US$ 503,85.-
 That is why Indonesia can’t access any soft loan from the World Bank.
note: only country with Per Capita less than US$ 500 can get a soft loan from the World Bank
 In fact, Indonesian income is dominated by the middle-lower income

9. Plausible Charts and Graphs
• Manipulating charts or graphs to convey
almost any desired impression.

10.  What do feel when
watching this chart?
 Same like before
 Graph 2 is more impressive

11. Presenting the Facts Without a
Reference Point
• Present a statistical result without suficient
data in presentation.
The graph tells us
students behavior
on everage is good.
The question:
What is definition of
those scale (0-10)

12. Exercise 1
“Students in Class Xo are good in mathematics.
Data shows the average of their mathematics’
score is above 7.”
• The Deceptive Sample
• The Misleading Average
• Plausible Charts and Graphs
• Presenting the Facts Without a Reference point

13. Please try
again
Sorry!! Wrong
answer..

14. Hmmm... I don’t
think that’s the
answer
Let’s check the
exercise one
more time!

15. back
That’s not the
answer

16. The Answer is….
The
Misleading
Average

18. Exercise 2
“The level of public health is
going worse.”
• The Deceptive Sample
• The Misleading Average
• Plausible Charts and Graphs
• Presenting the Facts
Without a Reference point

19. Please try
again
Sorry!! Wrong
answer..

20. Hmmm... I don’t
think that’s the
answer
Let’s check the
exercise one
more time!

21. back
That’s not the
answer

22. Presenting
the Facts
Without a
Preference
Point
What is the answer?

24. Exercise 3
“94% of Indonesian women agree that the Garnier light
cream can make their skin more shinning, 92% agree
the Garnier white cream can reduce oil in their face,
93% agree it can reduce black spot of acne.”
• The Deceptive Sample
• The Misleading Average
• Plausible Charts and Graphs
• Presenting the Facts Without a Reference point

25. Please try
again
Sorry!! Wrong
answer..

26. Hmmm... I don’t
think that’s the
answer
Let’s check the
exercise one
more time!

27. back
That’s not the
answer

28. Answer is…
The
Deceptive
Sample

30. Conclusion
• The good statistics are:
1. Sampling uses a random sampling method with
sufficient data to represent the total group.
2. There is no individual interests behind the survey.
3. No outlier in the data.
4. Don’t judge the fact by the graphs or charts.
5. Statistical output must attach a referenced point as
a comparison standard.