1 chapter 1. section 1-3. triola, elementary statistics, eighth edition. copyright 2001. addison...

1Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

MARIO F. TRIOLAMARIO F. TRIOLA EIGHTHEIGHTH

EDITIONEDITION

ELEMENTARY STATISTICSSection 1-3 Uses and Abuses of Statistics

2Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Uses of Statistics

Almost all fields of study benefit from the application of statistical methods

3Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Abuses of StatisticsBad Samples

4Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Definitions

self-selected survey (or voluntary response sample)

one in which the respondents themselves decide whether to be included

5Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Abuses of Statistics

Loaded Questions Misleading Graphs

Bad Samples Small Samples

6Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Bachelor High SchoolDegree Diploma

Figure 1-1 Salaries of People with Bachelor’s Degrees and with High School Diplomas

$40,000

30,000

25,000

20,000

$40,500

$24,400

35,000

$40,000

20,000

10,000

0

$40,500

$24,40030,000

Bachelor High SchoolDegree Diploma

(a) (b)

7Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

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

8Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Abuses of Statistics

Pictographs

Bad Samples Small Samples Loaded Questions Misleading Graphs

9Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Figure 1-2

Double the length, width, and height of a cube, and the volume increases by a factor of eight

10Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Abuses of Statistics

Precise Numbers Distorted Percentages Partial Pictures

Bad Samples Small Samples Loaded Questions Misleading Graphs Pictographs

11Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

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

12Chapter 1. Section 1-3. Triola, Elementary Statistics, Eighth Edition. Copyright 2001. Addison Wesley Longman

Bad Samples Small Samples Loaded Questions Misleading Graphs Pictographs Precise Numbers Distorted Percentages Partial Pictures

Abuses of Statistics

Deliberate Distortions