PSY201H1 Chapter Notes - Chapter 1: Scientific Method, Syllogism, Estimation Theory

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20 Nov 2012
Chapter One: Statistics & Scientific Method:
+ historically, humankind employed four methods to acquire knowledge: authority, rationalism, intuition and the
scientific method
+ use method of authority, something that is considered true because of tradition/because some person of
distinction says its true
- ie: may believe in a theory because a professor says it's true;; religion because of parents.
+ method is in disfavor and sometimes leads to error... although it is used a lot in living in daily lives
+ frequently accept a large amount of information on basis of authority – we don't have the time/the expertise to
check it out first hand
- ie: believe electrons exist although never seen one
+ uses reasoning alone to arrive at knowledge
- if premises are sound and reasoning is carried out correctly according to the rules of logic, then conclusions will
yield the truth
+ familiar with reason because we use it a lot
- ie: syllogism:
All statistics professors are interesting people
Mr. X is a statistics professor
Therefore Mr. X is an interesting person.
- assuming first statement is true, then it follows the second statement is true, the conclusion must be true
+ there are situations which reason alone is inadequate in determining the truth
- ie: John is suffering from depression... the cause can be psychological problems or inadequate diet – those are
two reasonable explanations for the phenomenon
- reason alone is inadequate in distinguishing between them so must resort to experience
- reason alone may be sufficient to yield truth in some situations, but it's clearly inadequate in others
+ scientific method also uses a reason to arrive at truth, but reasoning alone is only part of the process
- scientific method incorporates reason but is not synonymous with it
+ knowledge also acquired through intuition (sudden insight, the clarifying idea that springs into consciousness all
at once as a whole. Not arrived by reason. Idea often occur after conscious reasoning has failed. Or when
problems were set aside for awhile as well.)
+ uses both reasoning and intuition for establishing truth... its reliance on objective assessment is what
differentiates it from others.
+ scientific experiment: reasoning deductively from existing theory/inductively from existing facts/through
intuition, the scientist arrives at a hypothesis about some feature of reality.
- then designs an experiment to objectively test the hypothesis
- data from experiment then analyzed statistically, and the hypothesis is either supported/rejected
+ experiment provides basis for an objective evaluation of the hypothesis
+ data from the experiment force a conclusion consonant with reality
+ important aspect of this methodology: experimenter can hold incorrect hunches and the data will expose them
- hunches can be revisioned in light of the data and retested;; slow, has a self-correcting features that has a high
possibility of yielding truth in long run
population: the complete set of individuals, objects, or scores that the investigator is interested in studying. In
an actual experiment, the population is the larger group of individuals from which the subjects run in the
experiment have been taken.
Sample: a sample is a subset of the population. In an experiment, for economical reasons, the investigator
usually collects data on a smaller group of subjects than the entire population. This smaller group is called the
Variable: a variable is any property or characteristic of some event, object, or person that may have different
values at different times depending on the conditions. Height, weight, reaction time, and drug dosage are
examples of variables. A variable should be contrasted with a constant, which does not have different values at
different times.
Independent Variable (IV): the variable that is systematically manipulated by the investigator in an
Dependent variable (DV): the variable that the investigator measures to determine the effect of the
independent variable.
Data: measurements that are made on the subjects of an experiment
Statistic: a number calculated on sample data that quantifies a characteristic of the sample
Parameter: a number calculated on population data that quantifies a characteristic of the population.
+ ie: the average value of a population set of scores
+ statistic is calculated on a sample;; parameter calculated on a population
Scientific Research and Statistics:
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