Download - Methods of Research & Stats
The Scientific Attitude
The scientific attitude is composed of: curiosity (passion for exploration),
skepticism (doubting and questioning) and humility (ability
to accept responsibility when wrong).
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Scientific Method
Psychologists, like all scientists, use the scientific method to construct theories that organize, summarize and simplify
observations.
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A Theory is an explanation that integrates principles and organizes and
predicts behavior or events.
Example Theory: low self-esteem contributes to depression.
Theory
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A Hypothesis is a testable prediction, often prompted by a theory, to enable
us to accept, reject or revise the theory.
Example Hypothesis: People with low self-esteem are apt to feel more
depressed.
Hypothesis
Example Research: Administer tests of self-esteem and depression.
Individuals who score low on a self-esteem test and high on a depression
test would confirm our hypothesis.
Research Observations
Research Process
Case Study A technique in which one person is
studied in depth to reveal underlying behavioral principles.
Intensive investigation of one or more participants. Use of diaries, tests and interviews to
conclude research. Genie
Advantages?Disadvantages?
Naturalistic Observation
Observe subject in natural setting. 52 Psychology Students- 4 days-
captured 30 seconds of students’ waking hours every 12.5 minutes. 28% of time talking with another person 9% working on a computer
Advantages?Disadvantages?
Surveys A technique for ascertaining the self-
reported attitudes, opinions or behaviors of people usually done by questioning a representative, random sample of people 1. How many days a month do you miss school? 2. How many of those missed days are due to illness? 3. How many times have you gone to the doctor in the last month?
Survey
Wording can change the results of a survey.
Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. forbid)
Only 27% of Americans approved of “government censorship” of media sex and violence, while 66% approved of “more restrictions on what is shown on TV
“Aid the needy” vs.. “welfare”
Wording Effect
Survey Random Sampling
If each member of a population has an equal chance of inclusion into a sample, it is called a
random sample (unbiased).
If the survey sample is biased, its results are
not valid.
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Descriptive Methods
Case studies, naturalistic observation and surveys help to
describe behaviors.
Basically…
So many numbers! What do they all mean?!?!?
Stats Correlation: a measure of the extent to
which two factors vary together and thus how well either factor predicts the other
Correlation coefficient is a statistical index of the relationship between two things (from -1 to +1) and thus how well either one predicts the other
Ex. Knowing how much ACT scores correlate with school success tells us how well the scores predict school success
Correlation
When one trait or behavior accompanies another, we say the two
correlate.
Correlation coefficient
Indicates directionof relationship
(positive or negative)
Indicates strengthof relationship(-1.00 to 1.00)
r = 0.37+
Correlation Coefficient is a statistical measure of the relationship between two
variables.
Stats
Scatter plots: graphed cluster of dots each of which represents the values of two variables.
The slope of the points suggests the direction of the relationship between the two variables.
The amount of scatter suggests the strength of the correlation
Little scatter indicates high correlation
Stats
Positive correlation: two sets of scores tend to rise and fall together (0 to +1)
Negative correlation: two sets of scores relate inversely and as one goes up the other goes down (-1 to 0)
Weak correlation, indicating little relationship, has a coefficient near zero. Ex. Exercise and weight correlate negatively
Height and weight correlate positively
Stats
Positive or Negative?
High or low correlation?
Stats
Positive or Negative?
High or low correlation?
Stats
Positive or Negative?
High or low correlation?
Stats
Positive or Negative?
High or low correlation?
Stats Correlation and Causation
Correlations help us predict Low self-esteem correlates with
depression But does this prove that low self-esteem
leads to depression?
NO! CORRELATIONS AND STATISTICS DO NOT PROVE ANYTHING
Correlations show relationships between two variables but nothing more.
Illusory correlations
Illusory correlations are the perceptions of a relationship where none exists When we believe there is a
relationship between two things, we are more likely to notice and recall instances that confirm our belief
When we notice random coincidences we may forget that they are random and instead see them as correlated
Random Events
Given random data, we look for order and meaningful patterns.
Given large numbers of random outcomes, a few are likely to express order.
Angelo and Maria Gallina won two California
lottery games on the same day. An event that happens to but 1 in 1
billion people occurs about six times
every day, 2000 times a year.
Experiments- Key Words Defined Hypothesis- an educated guess Variable- any factor that is capable of
change Dependent variable- depends of what takes place
during the experiment. Independent variable- experimental factor/ can vary
independently of other factors.
Experimental group- the group to which an independent variable is applied
Control group- the group that is treated in the same way as the experimental group, but independent variable not applied.
Stats Experimentation
A research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable).
Example: Independent Variable: Breast milk or formula Dependent Variable: Intelligence score @ age 8
Experiments allow the researcher to focus on the possible effects of one or more factors by 1) manipulating the factors of interest 2) holding constant other factors
Stats
Stats Random Assignment
Assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between those assigned to the different groups If a behavior changes when we vary an
experimental factor, then we infer the factor is having an effect Unlike correlational studies, which
uncover naturally occurring relationships, an experiment manipulates a factor to determine its effect
Stats Random assignment is essential to getting
quality results and non-bias results Members who are assigned to research
groups are often blind (uninformed) about what treatment, if any, they are receiving In a double-blind study, neither the
participants nor the research assistants collecting the data will know which group is receiving the actual treatment In such studies researchers can check a
treatment’s actual effects apart from the participants’ belief in its healing powers
Placebo Effect
ComparisonBelow is a comparison of different
research methods.
Ask and define the question. Gather information and resources through
observation. Form a hypothesis. Perform one or more experiments and
collect and sort data. Analyze the data. Interpret the data and make conclusions
that point to a hypothesis. Formulate a "final" or "finished" hypothesis.