Download Chapter 2 - Huber Heights City Schools

Research in
Psychology
What is Research?
I. Pre-research decisions
A. First – ask a specific question & form hypothesis
B. Second – look for evidence using the appropriate method of
research.
1. Method of research depends on research topic
II.
Sample
A. A relatively small group out of the total population under study
1. Must be representative
a. random sample – each individual has an equal
chance of being represented
b. stratified sample – deliberately pick individuals
who represent the various subgroups
III. Methods of research
A. Naturalistic Observation
1. Used to observe natural behavior
2. Should be as unobtrusive as possible
a. Advantages – behavior is completely natural
b. Disadvantages – no interaction & behavior can be
interpreted incorrectly.
B. Case Study
1. Intensive study of a person or group
2. Combine long-term observations with diaries, tests and
interviews
a. Advantages – Background information may shed light
on present behavior.
b. Disadvantages – Can only be applied to one person &
not the population as a whole.
C. Surveys
1. Most practical way to gather data on attitudes, beliefs &
experiences of large #’s of people
2. Interviews, questionnaires
a. Advantages – Information can be gathered quickly,
cheaply & for the most part fairly accurate
b. Disadvantages – Sample may not represent the
population & results can be interpreted incorrectly
D. Longitudinal Studies
1. Studying the same group of people at regular intervals
over a period of years to determine change in behavior.
a. Advantages – best method to examine
consistencies and inconsistencies over time
b. Disadvantages – time-consuming
& concern about losing participants
D. Cross-Sectional Studies
1. Organize individuals into groups based on age
2. Random samples & each group is surveyed, tested or
observed simultaneously
a. Advantages – Representative & saves time and money
b. Disadvantages – cannot be used to study behaviors
over time
Correlations & Experiments
I.
Correlations & Experiments
A.
Correlation – describes how two sets of data relate to each
other.
i.
Positive correlations – as values of one variable increases
or decreases, the value of the second variable also
increases/decreases
1.
ii.
Examples –
a. higher hours studying = higher grades
b. lower education = lower wages
Negative correlations – as values of one variable
increases, the value of the second variable decreases and
vice versa
1.
Examples –
a. more days absent = lower grades
b. less education = more jail time
b. Experiments – allow researchers to control the situation and
decrease the likelihood of errors.
i.
Researchers think in terms of variables which are
conditions and behaviors subject to change.
1. independent – variable that is changed or altered to
observe the effects
2. dependent – variable that changes in relation to the
independent variable
a. Example
i. effect of education on income level
ii. Participants who are exposed to the independent
variable are in the experimental group.
iii. Those not exposed make up the control group.
Problems & Solutions in
Research
I.
Problems in research
A.
Self-fulfilling prophecy – having expectations about a
behavior & then acting in some way to carry out that
behavior.
B.
Two ways to avoid this:
i.
Single-blind study
a.
ii.
participants are “blind” in that they are unaware of
which are receiving treatment
Double-blind study
a.
participants AND experimenter are unaware of
which are receiving treatment
c. Regardless of what type of study, researchers must always
take into account a possible placebo effect
i.
II.
change in a patient’s illness or physical states that results
solely from the patient’s knowledge & perceptions of the
treatment
The Milgram Experiment
a. Good example of a single-blind study & a case for ethics
Statistical Evaluation
Statistics
A branch of math concerned with summarizing and making
meaningful inferences from collections of data.
2 types of Statistics
1. Descriptive Statistics –
The listing and summarizing of data in a practical,
efficient way.
A. frequency distribution – an arrangement of data
that indicates how often a particular score or
observation occurs.
B. normal curve – a graph
of normal distribution.
The bell-shaped curve.
C. measures of central tendency – a number that
describes something about the “average” score of a
distribution
1. mode – the most frequent score
2. median – the middle score
3. mean – the average score
4. variance (range) – a measure of how the scores
are spread out
D. standard deviation – describe the average distance of
every score from the mean
E. correlation coefficient – describes the direction and
strength of the relationship between two sets of
variables
2. Inferential Statistics
Used to make predictions or inferences about the data
and examines whether the data supports the
hypothesis or whether the results were due to chance.
A. probability – the chance that an outcome will
occur in a certain way
B. statistical significance – how likely that an
event or outcome is not due to chance.