Transcript Research and Statistics

Research and Statistics
Psychology 30
Chapter Objectives
 To understand the scientific method of research.
 To appreciate the methods, issues and challenges in
conducting research.
 To name the different types of psychological research and
some of the hazards of these.
 To organize and integrate new knowledge and
understandings within the discipline of psychology.
 To organize and integrate new knowledge and
understandings with other disciplines.
Journal Entry # 2
 My life as a statistic...
For the next 10 minutes, write a journal entry based on the
ways that you, the things you do, the things you enjoy, or the
things you don’t enjoy are measured.
For example: I am counted in the number of students that
attend Ituna School. I am counted as a person in my family. I
am counted as a member of the volleyball team.
http://www.online-stopwatch.com/
How do they know?
 How do researchers gather information, data, statistics and
specific research that when trying to create and prove their
hypothesis’?
Gathering Data
 Researchers use specific methods depending on the type of
research that they are trying to conduct.
 For example: A psychologist who is interested in personality
theories might begin with intensive case studies of individuals.
 The data that is gathered by researchers must be valid. Validity
is the process of verifying that a claim is correct, or
disproving it. When something is valid, it verifies the
researcher’s theory.
Samples
 Suppose a psychologist wants to know how the desire to get
into college affects the attitudes of high school juniors and
seniors. It would be impossible to study every junior and
senior in the country. Instead, the researcher would select a
sample, a relatively small group of the total population
under study- in this case, all high school juniors and seniors.
Samples
 Samples must be representative of the population a
researcher is studying.
 If we wanted to know how tall the average grade 12 boy at Ituna School
was, we would want to make sure that our sample included both short
and tall boys in our school so that our sample itself would not be biased.
 There are two ways of avoiding a biased sample.
o Random sample: taking a sample at random, like drawing names
from a hat and having those boys be part of the study
o Stratified sample: deliberately choosing individuals who represent
various heights in our school, some short, some “medium” and
some tall young men.
Correlations and Explanations
 Correlations are used in descriptive studies when scientists
or researchers want to observe and describe.
 Correlations describe the degree of relatedness between
two sets of data. There are two types of correlations,
positive correlations and negative correlations.
Positive Correlations
 There is a positive correlation between high IQ scores
and high academic success. High IQ scores tend to go with
high grades.
 There is a negative correlation between smoking
cigarettes and living a long and healthy life. The more a
person smokes, the fewer years he or she may live.
 Can you think of 5 positive correlation statements and 5
negative correlation statements?
Experiments
 How are experiments conducted? (Handout)
 Experiments enable the researcher to control the situation
to decrease the possibility that unnoticed, outside factors will
influence the end result.
 Experiments are meant to prove or disprove
hypothesis’.
Variables
 When scientists conduct experiments they think in terms of
variables. Variables are conditions and behaviors that are
subject to a variation or change.
 There are two types of variables. Independent variables
and dependent variables. Can you guess what these two
variables entail?
Independent Variables
 The independent variable is the variable experimenters
manipulate so they can observe its effects.
Example:
Effect of drug dosage on symptom severity
In a study of how different doses of a drug affect the severity of symptoms, a researcher could
compare the frequency and intensity of symptoms when different doses are administered.
Here the independent variable is the dose.
Dependent Variables
 Dependent variables are the variables that researchers
believe will be affected by the independent variable.
Example:
Effect of drug dosage on symptom severity.
In a study of how different doses of a drug affect the severity of symptoms, a researcher could
compare the frequency and intensity of symptoms when different doses are administered.
Here the independent variable is the dose and the dependent variable is the
frequency/intensity of symptoms.
Other Variable Examples
Effect of education on wealth
 In sociology, in measuring the effect of education on income or
wealth, the dependent variable is level of income/wealth and the
independent variable is the education level of the individual.
Effect of time on speed (measurement of acceleration)
 In measuring the acceleration of a vehicle, speed varies with time
but time does not vary with speed. Here, time is the independent
variable, and speed is the dependent variable
Experimental Groups
 Subjects who undergo experiments are referred to as
experimental groups.
 Because there is a chance that people will act differently in a
controlled environment scientists and researchers often
set up two different groups, an experimental group and a
control group.
 Control Groups are treated the same way as the subjects in
the experimental group, except that the experimental
treatment is not applied.
Control Groups are a MUST!
 Control groups are absolutely necessary in experiments
because without them a scientist or researcher can’t be
certain that the experimental group is actually reacting to
what he or she thinks it is reacting to.
Control Group Examples
 “One example might be testing plant fertilizer by giving it to
only half the plants in a garden: the plants that receive no
fertilizer are the control group, because they establish the
baseline level of growth that the fertilizer-treated plants will
be compared against. Without a control group, the
experiment cannot determine whether the fertilizer-treated
plants grow more than they would have if untreated.”
http://en.wikipedia.org/wiki/Scientific_control
 Greys Anatomy Example
Studies
 Case Studies are scientific biographies of an indivudla group.
Most case studies focus in a particular disorder or experience.
(We experienced this when we watched the story of Genie.”
 Surveys are sometimes thought of as “impersonal” but are the
most practical way to gather data on the attitudes, beliefs, and
experiments of large numbers of people. A survey can take the
form of interviews, questionnaires or a combination of the two.
 Longitudal Studies cover long periods of time, making them
time consuming and precarious. However, they are a great way to
study consistencies and inconsistencies over a long period of time.
 Cross- Sectional Studies are studies that divide the
experimental groups into small groups, often based on age
categories.
Survey Assignment
 In groups of two or three people, you will be asked to create a
survey to administer students or teachers at Ituna School.
 You will need to make sure that you come up with a question or
hypothesis at the beginning of your survey planning process so that
you are clear about exactly what your group is looking for.
 Each person in the group will be responsible for writing a one
page summary of the survey process including the group’s initial
hypothesis, the experimental group chosen, the survey results and
a summary of your group’s hypothesis.
Avoiding Errors in Doing Research
 No matter how objective humans or scientists may try to be,
there is always a chance that we will find exactly what we are
trying to find, overlooking important evidence.
 Has this ever happened to you?
 This is known as the self-fulfilling prophecy.
How do we avoid the Self-fufilling
Prophecy?
 We can avoid this by using what is known as the double
blind technique.
 Suppose a psychologist wants to study the effects of a
particular tranquilizer. She might give the drug to an
experimental group and a placebo (a harmless substitute for
the drug) to a control group. The next step would be to
compare their performances ona serioes of tests. This is a
single blinded experiment. The subjects are “blind” in the sense
that they do not know whether or not they have received the
tranquilizer or the placebo.
Double Blind Experiments
 Double blind experiments take place when both the
researcher also doesn’t know which people in the group are
actually part of the control group and who are not. This type
of experiment eliminates the possibility that the researcher
will unconsciously find what they expect to find regarding
the use of the drug, or the hypothesis they have formulated.
What are some of the ethical issues in
research?
 Confidentiality is the right of privacy for subjects concerning their participation in
research. All steps must be taken to assure that subjects’ participation is confidential. If
any possibility exists that someone other than the researcher may have access to the data,
the subjects must be informed of this possibility before they provide their informed
consent to participate (Buskist, Carlson, Enzle and Heth, 1997, p. 42).
 Informed consent requires that potential subjects understand exactly what is expected
of them during the course of the research and that the investigator protects participants
from physical and psychological discomfort, harm, and danger (Buskist et al., 1997, p.
42).
 Debriefing requires that research participants be given full information about all aspects
of the study after they have participated in it, thus assuring that they leave with a full
understanding of its purpose, and receive a full disclosure of the information gathered
(Baron et al., 1998, p. 31).
Descriptive and Inferential Statistics
 Read the information found on pages 509-513 of your
textbook. Be sure to make notes on the different kinds of
statistics and be able to differentiate between the two.
 Which type of stats would you argue is most useful when
summarizing information? Why?
Mode, Median and Mean Review
 The mode is the most frequent score. In a graph, the mode is the
peak of the graph.
 The median is the middle score.
 The mean is what most people think of as the average, and is
most commonly used to measure the central tendency.
 Central Tendency is a number that describes something about
the “average” score.