AP Psychology Research Methods Review
which of the following is the strongest correlation coefficient -0.83, +0.10, or +0.64
-0.83 because correlation becomes stronger as it approaches -1.0 or +1.0 -0.83 correlation means that there is a very strong inverse relationship
voluntary participation
-all participants must be voluntary -participants should be told that they are free to withdraw from research at any time
alternative research activities
-many college courses include research participation as a course requirement -all students must be given an option to chose an alt activity of equal value
inferential statistics
-most experiments are conducted with a small sample of subjects -psychologists want to generalize the results from their small sample to a larger population
standard deviation
-the most widely used measure of variation -a standard measurement of how much the scores in a distribution deviate from the mean
advantages of experiments
1. Enables researchers to identify cause-and-effect relationships 2. Enables researchers to distinguish between real and placebo effects 3. Enables researchers to manipulate the independent variable and measure the dependent variable 4. Enable researchers to control bias by using a double-sided study 5. Enable researchers to replicate a study thus increasing confidence that the independent variable influences the dependent variable
what must happen after deception occurs
subjects must be debriefed to explain the true purpose of the study and clear up any misconceptions or concerns
hypothesis
tentative statement that describes the relationship between two or more variables MUST be testable, verifiable, and refutable
what does a zero correlation indicate
that there is no relationship between two variables
what does a positive correlation indicate
that two variables move or vary in the same direction
deception
the American psychological association justified the need for some deception in certain research areas
normal distributions form
the bell shaped curve
population
the entire group a researcher wants to study
how does an experiment work
the experimenter purposely manipulates and controls selected variables in order to determine cause and effect
dependent variable
the factor that is measured by the experimenter. if is affected by and thus dependent on the independent variable
range
the highest score in a distribution minus the lowest score
what do extreme scores have the greatest impact on
the mean than on the mode or the median
the smaller the p value....
the more significant the results; a p value can never equal 0 because researchers can never be 100 percent certain that the results did not occur to chance
mode
the most frequently occurring score in a distribution
informed consent
the participants agreement to take part in a study after being told what to expect; researchers must obtain the participants permission, or their parent or guardian's permission before the study begins
median
the score that divides a frequency distribution exactly in half, so that the same number of scores lie on each side of it
what are inferential statistics used for
to determine how likely it is that a study's outcome is due to chance and whether the outcome can be legitimately generalized to the larger population fro which the sample was selected
what does a negative correlation indicate
two variables move or vary in opposite directions
purpose of control
used to ensure that all groups in the experiment are treated exactly the same except for independent variable
experimenter bias
when a researcher's expectations or preferences about the outcome of a study influence the results in a hoped-for direction
sample bias
when research participants are not representative of the larger population
when is deception only justified
when there is no alternative and the findings justify the use of deception because scientific, educational, or applied value
a study by isabelle deltoid for the danish cancer society found no correlation between cell phone use and incidence of brain tumors this is an example of
zero correlation
placebo
an inactive substance or fake treatment often used as a control technique in a drug research
mean
average score; sum of a set of scores
naturalistic observation
researchers unobtrusively observe the behavior of subjects as it occurs in a real social setting
disadvantages of experiments
1. create artificial laboratory conditions that do not correspond to real-life situations 2. can be compromised by confounding variables that are difficult to identify and control 3. susceptible to researcher and participant biases 4. raise ethical concerns when subjects are deceived
animal research studies five steps
1. must have clear scientific purpose 2.must provide human living conditions for animal subjects 3. must legally acquire animal subjects from accredited companies 4. must employ least amount of suffering feasible 5. less than 10% of research is done with nonhuman animals...ninety percent of the nonhuman animals are rats mice and pigeons
advantages of correlation studies
1. they can be used to describe or clarify a relationship between two variables 2. they can be an efficient way to utilize preexisting data 3. they can be used to dispel illusory correlations
disadvantages of correlation studies
1. they cannot be used to establish cause and effect relationships 2. they cannot be used to establish the direction of causal influence 3. they do not allow researchers to actively manipulate the variables 4. they make it difficult to identify the impact of confounding variables
what does descriptive research not allow
researchers to establish a cause-and-effect relationship
experiment
a carefully controlled method of investigation used to establish a cause and effect relationship
any change in the highest score in any distribution must result in
a change in the mean
statistically significant difference
a difference not likely due to chance; by consensus, a statistically significant difference is one that would show up only five percent of the time or less
operational definitions
a precise description of how the variable in a study will be manipulated and measured
double-blind study
a procedure in which neither the researcher nor the participant knows which group received the experimental treatment. The procedure receives the experiment bias
single-blind study
a procedure in which the subjects do not know whether they are in the experiment or control group
surveys
a research technique that uses questionnaires or interviews or a combo of the two to assess the behavior, attitudes and opinions of a large number of people; researchers generally only question a sample of the population whose opinions they seek to assess
measure of variation
a single score that presents info about the spread of scores in a distribution
what does naturalistic observation provide
a slice of life that can be very revealing, however, it is important to remember that these observations are descriptive and do not explain behavior
confidentiality
all info about participants must remain private; researchers may not compromise the privacy of research participants
how are correlation coefficients calculated
by a formula that produces a number ranging from +1.00 to -1.00
correlation does not prove
causation
cross-sectional method
compares individuals of various ages at one point in time; ex: a cross-sectional study of achievement motivation would test eighth, tenth, and twelfth grade students at the beginning of the school year; provides info about age differences, difficult to make generalizations since cross-sectional studies measure behavior at only one point in time
negatively skewed distribution
contains a preponderance of scores on the high end of the scale; mean will be lower than the median making median a better representative of central tendency than the mean in a negatively skewed distribution
positively skewed distribution
contains a preponderance of scores on the low end of the scale; mean will be higher than the median and is thus a better representation of central tendency than the mean in a positively skewed distribution
strength of correlation weakens as...
correlation coefficient approaches 0.00
confounding variable
differences between experimental group and the control group other than the independent variable; have unwanted influence on the outcome of an experiment
what does having a control group allow experimenter to do
enables experimenter to make comparisons with the experimental group
what can case studies not be used to do
establish cause-and-effect relationships; they are susceptible to inaccurate reporting and the subjects biased views
random sample
every person in the population has an equal chance of participating, helps to minimize the bias, and ensures that the sample is representative
problems that could occur with a control
experimenter bias sample bias
independent variable
factor that is manipulated or controlled by the experimenter
experimental group
group exposed to independent variable
control group
group of participants who are exposed to all experimental conditions except the independent variable
case study
in-depth examination of a SINGLE research participant
what is descriptive research
includes methods that enable researchers to observe and describe behaviors and mental processes without manipulating variables
in a study measuring the impact of playing violent video games and aggression in children, what would potential confounding variables be
income level of children's parents and incidence of abuse
an experimenter wants to determine the relationship between rehearsal/repetition of list of definitions of difficult SAT vocabulary words and later recall these definitions
independent: amount of rehearsal/repetition dependent: recall of correct definitions
an experimenter wants to determine if playing violent video games increases the frequency of aggressive behavior in children. what are the independent and dependent variables?
independent: the type of video game played dependent: aggressive behavior exhibited by children
longitudinal method
measures a single individual or group of individuals over an extended period of time; ex: a longitudinal study of intelligence would retest the same people over a period of years; provide in-depth info but can be expensive and time consuming
as levels of education increase expressions of anger decrease this is an example of
negative correlation
correlation coefficient
numerical value that indicates the strength and direction of the relationship between two variables
what do case studies enable a researcher to do
obtain detailed knowledge about a person. they also provide an opportunity to conduct in-depth studies of rare and unusual cases
a study measuring the relationship between rehearsal/repetition and recall of difficult SAT vocabulary words, rehearsal might be...
operationally defined as the number of times the subject reads aloud a list of words; difficult words might be operationally defined as answers to level 5 SAT sentence completion questions. The recall might be operationally defined as the percentage of words that are correctly defined
what is a downfall of surveys
participants often report that they are healthier, happier, and less prejudiced than would be expected based upon the results of other types of research; this phenomenon is known as social desirability
as frequency of smoking increases, so does incidence of lung cancer this is an example of
positive correlation
what do correlation studies indicate
possibility of cause and effect relationship
p value
probability of concluding that a difference exists when in fact this different does not exist
random assignment
procedure by which participants are assigned to experimental and control groups by chance. this minimizes any pre-existing differences between those assigned to the different groups
correlation studies
researchers observe or measure a relationship between variables in which changes in one variable are reflected in changes in other variable; do not directly manipulate the variables can be used to analyze the data gathered in any type of descriptive method
