statistics and casual generalization

7/31/2019 Statistics and Casual Generalization

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Statistics
http://www.suicidology.org/associations/1045/files/statistics.jpehttp://www.suicidology.org/associations/1045/files/statistics.jpe


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Statistics are pieces of data that aregathered and analyzed to provideinformation that can have an impact on our

lives.

On the following pages is a historical story

showing how the use of statistics can makea difference.


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It was the year 1840.

The place was London,

England.
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Thousands of people in the cities were dying of a

mysterious disease called cholera. There was no

known cure and no one knew what caused thedisease. What was especially frustrating was that

it was unclear why people contracted the disease

while others did not.


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Doctor John Snow, a

London doctor,

decided to place dotson a map of London to

represent each

cholera death.


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He found out that there was a

connection between thecholera deaths and onewater pump on Broad Streetin London. It became veryclear that something wascontaminating the water at

this pump and killingthousands of people.

Dr. Snows use of statistics ledto changes that savedthousands of lives.


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Statistical Evidence and its uses

Statistical evidence can be gathered from

polling a sample of a target population about

a given topic.

Uses of Statistics:

Political Party

Media Advertisers

Doctors


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How the research is done

Need to consider three questions

1. What do I need to find out

This is called characteristic of interest2.Whom do I want to know(target population)

3.Whom can I study to get the accurate answers

about my entire population


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For a study to be accurate and reliable

The sample must be large enough

The sample must represent the target

audience

The sample must be random


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Question to be asked about statistical

reports

What is the sample size Is the sample representative in all significant

characteristics and in the proportion of those

characteristics ?

Have all significant characteristics been considered ?

Is the study is a poll, are the questioned biased?

What is the credibility of the polling organization or

research institute?

Is the survey biased because of the vested interest of

the company tat paid for it ?


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Generalizations Inductive argument move from things

known to things unknown.

Sample- item or items we know

something about. Target class- group of items to which we

wish to extend our knowledge.


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Types of Generalizations

Statistical Generalization

Analogical Generalization

Causal Generalization


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Statistical Generalization

Draws a conclusion about a portion ofthe target group.

1/5 of adult Americans are obese. More teenagers die of accidents related to alcohol

than do adults.

Most jungles are hot.


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Analogical Generalization

Draws a conclusion about a target itemon the basis of a shared similarity orsimilarities.

This pair of shoes, like these shoes, is made ofleather, has the same style and same maker. Thus,like these shoes, this new pair of shoes will becomfortable.


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Causal Generalization

Draws a conclusion about anobserved relationship, i.e., that thisrelationship will always occur, on

the basis of previously observedinstances of the relationship.


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Example

at time 1, y follows x.



etc.

Thus, x causes y.


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DAVID HUME (1711-1776)


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MEMORY AND CAUSATION

Hume says that memoryis the main source of personal identity.Had we no memory, we never should have any notion of

causation, nor consequently of that chain of causes and effectswhich constitute our self or person.

Memory is the source of our knowledge of causation, but havingonce acquired this notion of causation from the memory, we canextendthe same chain of causes, and consequently the identity ofour persons beyond our memory, and can comprehend times, andcircumstances, and actions which we have entirely forgot, butsuppose in general to have existed.

In this view, therefore, memory does not so much produce asdiscoverpersonal identity, by showing us the relation ofcause andeffectamong our different perceptions.


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SUMMARY OF HUMES THEORY OF

THE SELF

The self for Hume is not a simple, unchanging entity of which weare aware in experience. Rather, we are only aware of a number ofthings in sensation and reflection - data of the external and internalworld - which succeed one another rapidly in time. We can mistakethe rapid succession of resembling perceptions for a self, but as no

perception or experience is constant and unchanging, we are notreally aware of anything which we can call a self at all.

This is called the bundle theory of the self, and there is no needtosuppose that a substance underlies the bundle to give it support, orto bind its perceptions together.

Memoryand causation are most important to the sense we have ofpersonal identity over time.


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A PROBLEM FOR HUME

Recall that Hume says that every idea must originate from a priorimpression, and as there is no impression of a simple, unchanging self inexperience, then we have no idea of such a self. This results in a problemfor Hume in that, as M. A. Notturno notes, if Humes theory of ideas weretrue, then he should not be able to understand the very idea of the theory

which he is criticizing. How could Hume understand what the termssimple, unchanging self are meant to signify if all ideas are dependent onprior impressions, and there is no impression of a simple, unchanging selfin experience? And if he cannot understand it, then how can he argueagainst it?

Even if it is false that we find a simple, unchanging self in experience it

seems nevertheless true that we understand the idea of such a thing. But,once again, by Humes own theorizing about the origin of ideas inexperience he should not be able to understand the very theory which hesays is untrue.


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Theory of Technical Causation

Necessary condition

A sufficient condition

Multiple causesImmediate causes

statistics and casual generalization

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