24 Lie With Statistics

8/2/2019 24 Lie With Statistics

1/7

11/17/

How to Lie with Statistics

Whats This All About?Statistics are commonly used to deceive

Technically true, but deceptive

Preys on fear of numbers

Math is hard! --Barbie

False im ressionof accurac

There are three kinds of lies:

Lies, Damned Lies, and Statistics.

--attributed to Benjamin Disraeli

Figures never lie, but liars figure.

Need to know how to lie with statistics,to keep from being lied to with statistics.

Ways to Lie to Voters0) Fabrication

Just make things up

Can be very effective:

Lyndon Johnson:

Make the son of a bitch deny it.

Swift Boat Veterans for Truth

Also talking about ways to say things that are true, but misleading


2/7

11/17/

"I guess I should warn you that if I turn out to beparticularly clear, you've probablymisunderstood me.

-Alan Greenspan at his 1988 confirmation hearings.

Ways to Lie to Consumers: Omission

Leave Things Out

E.g., use mean, but mode may better tell the story

Sibling Distribution

dants

40

50

60

Siblings

Most people have 0,1,2

Mean

Median

Few people with huge families

Pull mean up

Number of Siblings

0 2 4 6 8 10

#Respo

0

10

20

30


3/7

11/17/

Age Distribution

ants

25

30

35

Age (of students and faculty)

Median

Diverse Population Problem

Students, mostly 19-22

(Much) older faculty

Age

20 30 40 50 60

#ofRespond

0

5

10

15

20

Mean

Nobody at mean age

Very bad descr iption

Other Examples

Facts:

Tax Cut

111 million taxpayers willsave, on average, $1,586 off

their taxes.

1) 25% receive NO cut

(drops mean to $1,217)

2) Median cut: $470

Half of all taxpayers get $470 or less

The Fifth Dentist Problem

Four out of five dentists surveyed

How many dentists total?

Five not a good sample

Four out of five cards

drawn from this deck were black!

Leave out the sample size, and you can

prove just about anything

Ways to Lie to Consumers: Exaggeration

Make Something of Nothing

Fear of big numbers:

My opponent wants to spend $2 million on

[something]

Sounds badbut,

$2 million = 1/1,000,000th of the budget

Need to put big numbers in context

Numbers dont lie,thats where we comein!


4/7

11/17/

Guys Rule!Gender Distribution

pondants 75

100Honest presentation

Full scale shownBars same width, color

Slightly more male studentsNot a bi difference

Male Female

%o

fRes

0

25

Example: Guys Rule!More Survey Data

Scale axes to blow up small

differences

Nothing false in graph, but

creates false im ression

Gender Distribution

pondants

50

52

54

56

Male Female

%o

fRe

44

46

48

0

50,000

100,000

150,000

19 20-29 30-39 40+

Average Income

Average Income

Average Income

0

50,000

100,000

150,000

200,000

250,000

300,000

19 20-29 30-39 40+

Average Income

Average Income

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

19 20-29 30-39 40-49 50-59 60+

Average Income

Average Income

A I

050,000

100,000

150,000

200,000

250,000

300,000

19 20-29 30-39 40-49 50-59 60+

Average Income

Average Income


5/7

11/17/

Frequency Bully Others BulliedNever 55.7% 58.9

Rarely 25.0 24.2

Sometimes 10.6 8.5

Weekly 8.8 8.4

Bully OthersGood of bad statement: About the same percentage of kidsbully others and are bullied

Bullied: The claim that 41.7% of students face a degree of bullyingis not a lie However, it would have been equally true to claim that only16.9% of students were victims of bullying sometimes orweekly

This map shows how people in differentstates of the US like pizza. (These datawere made up).The code for the state color is:Red States = People Love PizzaYellow States = People Like PizzaPurple States = People Hate Pizza

The map really doesn't say very much. We don't know

how it was determined that people like pizza...were people asked if they liked pizza?

Were people asked how much pizza they ate in a week? a month? a year?

Was the number of pizzas purchased at stores in different states counted?

Was the number of pizza restaurants in different states counted?

We also do not know

if there are any re al differences between how much people like pizza in the different states.

How much do people love pizza in California?

What is the difference between how much people love pizza in Utah compared to how much they like pizza inNevada?

There are no scales or measurements to indicate any of this information. Although this type of graphicgives almost no information, it is used frequently in many popular magazines.

Another example, who cares if in our elections a stateis blue or red since it is the electoral votes that count

What to Do?

Questions to ask about any statistic:

1) Who created it?

Do they have an agenda?

y was crea e

Research or politics?

3) How was it created?

Methodology


6/7


7/7

11/17/

A lot of presented data is truthful

Most people are willing to present unbiasedstatistics

We are learning how to read and interpret

Documents

24 Lie With Statistics