1. STATISTICS ELEMENTARY MARIO F. TRIOLA
Section Uses and Abuses of Statistics
MARIO F. TRIOLA
EIGHTH
EDITION

2. Uses of Statistics
Almost all fields of study  benefit from the application  of statistical methods
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3. Abuses of Statistics
Bad Samples

4. Definitions self-selected survey (or voluntary response sample)
one in which the respondents themselves decide whether to be included
One of the most common methods of bad sampling

5. Abuses of Statistics Bad Samples Small Samples Loaded Questions
Misleading Graphs

6. Figure 1-1 Salaries of People with Bachelor’s Degrees and with High School Diplomas
$40,500
$40,500
$40,000
$40,000
35,000
30,000
$24,400
30,000
20,000
$24,400
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Graphs whose vertical scales do not start at 0 will give a misleading representation of the differences in heights of the bars.
25,000
10,000
20,000
Bachelor High School
Degree Diploma
Bachelor High School
Degree Diploma
(a)
(b)

7. We should analyze the numerical information given in the graph instead of being mislead by its general shape.

8. Abuses of Statistics Bad Samples Small Samples Loaded Questions
Misleading Graphs
Pictographs

9. Double the length, width, and height of a cube, and the volume increases by a factor of eight
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Figure 1-2

10. Abuses of Statistics Bad Samples Small Samples Loaded Questions
Misleading Graphs
Pictographs
Precise Numbers
Distorted Percentages
Partial Pictures

11. “Ninety percent of all our cars sold in this country in the last 10 years are still on the road.”

12. Abuses of Statistics Bad Samples Small Samples Loaded Questions
Misleading Graphs
Pictographs
Precise Numbers
Distorted Percentages
Partial Pictures
Deliberate Distortions