scientific method
general procedures psychologists use for gathering and interpreting data
Define theory as it relates to research methods.
organized, testable explanation of phenomena
Other researchers must be able to replicate the results of an experiment to validate its conclusions.
What is replication?
obtaining similar results to a previous study using the same methods
What is hindsight bias?
explaining why something happened after it has occurred
What is a controlled experiment?
researchers systematically manipulate a variable and observe the response in a laboratory
hypothesis
prediction of how two or more factors are related
What is the difference between an independent variable and a dependent variable in an experiment?
The factor being manipulated is the independent variable. The factor being measured is the dependent variable.
If students use Brainscape to study, rather than simple flash cards, then they will get higher test scores.

independent: method of studying

dependent: test score
Define population as it relates to research methods.
all the individuals to which the study applies
Define sample as it relates to research methods.
subgroup of a population that constitutes participants of a study
What type of sample should be used in research?
Larger sample sizes are ideal because they are the most representative of the population.
The amount of difference between the sample and population is called __________.
sampling error
Define random selection as it relates to research methods.
every individual from a population has an equal chance of being chosen for the sample
Which individuals are in the experimental group?
subjects who receive the treatment or manipulation of the independent variable
Which individuals are in the control group?
subjects who do not receive any treatment or manipulation
Subjects who receive the treatment are part of the __________, while those who do not receive the treatment belong to the __________.
experimental group; control group
What type of experimental design uses experimental and control groups?
A betweensubjects design uses an experimental group and a control group to compare the effect of the independent variable.
What process is used to ensure there are no preexisting differences between the control group and the experimental group?
Random assignment fairly divides the sample participants into the two groups.
confounding variable

any difference between the experimental group and the control group, besides the effect of the independent variable

a.k.a. third variable
List four types of confounding variables.

experimenter bias

demand characteristics

placebo effect

lack of counterbalancing
Define experimenter bias as it relates to confounding variables.
Experimenter bias occurs when a researcher's expectations or preferences about the results of the study influence the experiment.
Define demand characteristics as they relate to confounding variables.
clues the participants discover about the intention of the study that alter their responses
Define placebo effect as it relates to confounding variables.
responding to an inactive drug with a change in behavior because the subject believes it contains the active ingredient
Define counterbalancing as it relates to confounding variables.
Researchers using a withinsubjects design eliminate the effects of treatment order by assigning half the participants to treatment A first and the other half to treatment B first.
What type of experimental design uses each participant as his/her own control?
A withinsubjects design exposes each participant to the treatment and compares their pretest and posttest results. This design can also compare the results of two different treatments administered.
How do researchers specifically define what variables mean?
Researchers use operational definitions to precisely describe variables in relation to their study. For example, "effectiveness of studying" can be operationally defined with a test score.
What is a singleblind procedure?
research design in which the subjects are unaware if they are in the control or experimental group
What is a doubleblind procedure?
research design in which neither the experimenter nor the subjects are aware who is in the control or experimental group
Singleblind procedures aim to eliminate the effects of __________, while doubleblind procedures use a third party researcher to omit the effects of __________.
demand characteristics; experimenter bias
What is the Hawthorne effect?
individuals who are being experimented on behave differently than in their everyday life
How are quasiexperiments different from controlled experiments?
Random assignment is not possible in quasiexperiments.
What types of research are considered quasiexperiments?
Differences in behavior between:

males and females

various age groups

students in different classes
correlational research

establishes a relationship between two variables

does not determine cause and effect

used to make predictions and generate future research
List three types of correlational research.

naturalistic observation

surveys

tests
Define naturalistic observation as it relates to correlational research.
Naturalistic observation consists of field observation of naturally occurring behavior, such as the way students behave in the classroom. There is no manipulation of variables.
What are surveys and why are they not always accurate?

type of correlational research

questionnaires and interviews given to a large group of people about their thoughts or behavior

individuals aim to be politically correct and socially accepted, leading them to give false answers
Define tests as they relate to correlational research.
research method that measures individual traits at a specific time and place
__________ studies start by looking at an effect and then attempt to determine the cause.
Ex post facto
What is the difference between the reliability and validity of a test?
A test is reliable if it is consistent and repeatable, meaning if you could take the same test a second time, you would get the same result(s)
A test is valid if it measures what it is intended to measure. It is often said that a test cannot be valid if it is not reliable.
For example, a bathroom scale is reliable because you can weigh yourself, step off, step back on, then get the same measurement. The bathroom scale is valid for measuring how much you weigh, but invalid for measuring your IQ.
What is a case study?

detailed examination of one person or a small group

beneficial for understanding rare and complex phenomena in clinical research

not always representative of the larger population
experiments
Strengths:
 determine cause and effect relationship between variables
 control over confounding variables
Weaknesses:
 it can be difficult to generalize from the lab to the real world
 expensive
 timeconsuming
correlational research
Strengths:
 easy to administer surveys or tests
 inexpensive
 minimal time needed
 substantial realworld generalizability
Weaknesses:
 no control over confounding variables
 skewed or biased results
 establishes a relationship, not causation
statistics
analysis of numerical data regarding representative samples
__________ data includes numerical measurements and __________ data includes descriptive words.
Quantitative; qualitative
What are the four scales of measurement?

nominal

ordinal

interval

ratio
nominal scale
numbers have no meaning except as labels
Example:
Girls are designated as 1 and boys are designated as 2.
ordinal scale
numbers are used as ranks
Example:
The highest score is designated as 1, second highest as 2, third highest as 3, and so on.
interval scale
numbers that have a meaningful difference between them
Example:
Temperature: The difference between 10°F and 20°F is the same as between 30°F and 40°F.
ratio scale
numbers that have a meaningful ratio between them on a scale with a real zero point
Example:
Weight and height: If you weight zero pounds, you have no weight. 100 pounds is twice as heavy as 50 pounds.
Would temperature be measured on an interval scale or a ratio scale?
interval
If the temperature is 0°F, there is not "no temperature." There is not a meaningful ratio between values. 100°F is not twice as hot as 50°F.
What are descriptive statistics?
numbers that summarize a set of research data from a sample
frequency distribution
an orderly arrangement of scores indicating the frequency of each score
What is the difference between a histogram and a frequency polygon?
A histogram is a bar graph and a frequency polygon is a line graph or a bell curve.
central tendency
Measures of central tendency describe the most typical scores for a set of research data.
 mode
 median
 mean
mode
most frequently occurring score in the data set
median
the middle score when the data is ordered by size
mean
arithmetic average of the scores in the data set
If two scores appear most frequently, the distribution is __________, and if there are three or more appearing most frequently, it is __________.
bimodal; multimodal
Which measure of central tendency is the most representative? The least representative?

mean is usually most representative, unless there are extreme outliers that pull the mean in a particular direction

median is less sensitive to outliers, but is a weak statistic

mode is the least representative
normal distribution
bellshaped, symmetric curve that represents data about many human characteristics throughout the population
When most of the scores are compacted on one side of the bell curve, the distribution is said to be __________.
skewed
Positively skewed distributions include a lot of small values and negatively skewed distributions include a lot of large values.
measures of variablity
Measures of variability describe the dispersion of scores for a set of research data.
 range
 variance
 standard deviation
range
difference between the largest score and the smallest score
What do variance and standard deviation measure?
average difference between each score and the mean of the data set
Taller, narrow curves have less variance than short, wider curves.
What is a z score (a.k.a. standard score)?

allows for comparison between different scales

subtract mean from each score and divide by standard deviation

mean has a z score of zero
percentile score
percentage of scores at or below a particular score between 1 and 99
Example:
If you are in the 70th percentile, 70% of the scores are the same as or below yours.
Pearson correlation coefficient

statistical linear measure of the relationship between two sets of data

varies from 1 to +1

helps to make predictions about variables

perfect positive correlation

no relationship

perfect negative correlation

r = +1
direct relationship: as one variable increases or decreases, the other does the same

r = 0
no relationship

r = 1
inverse relationship: as one variable increases or decreases, the other does the opposite
direct relationship: as one variable increases or decreases, the other does the same
no relationship
inverse relationship: as one variable increases or decreases, the other does the opposite
What type of graph plots single points to show the strength and direction of correlations?
scatterplot
What is the term for the line on a scatterplot that follows the trend of the points?
line of best fit or regression line
inferential statistics

used to interpret data and draw conclusions

indicate generalizability to population

indicate real relationship, not due to chance
What is the difference between a null and an alternative hypothesis?
Null hypotheses state that a treatment had no effect, while alternative hypotheses state the treatment did have an effect in the experiment.
What is the difference between a Type I and Type II error?
Type I errors, or false positives, occur if the researcher rejects a true null hypothesis. Type II errors, or false negatives, occur if the researcher fails to reject a false null hypothesis.
The variable p represents __________.
statistical significance
When is a finding statistically significant?
when the probability (alpha) that the finding is due to chance is less than 1 in 20 (p < 0.05)
Said another way, when you are 95% confident that the result was not due to chance
What method statistically combines the results of several research studies to reach a conclusion?
metaanalysis
Why did the American Psychological Association (APA) implement ethical guidelines?

Guidelines were set in place in the late 20th century to stress responsibility and morality in research and clinical practice

Dangerous and inhumane experiments such as Harlow's rhesus monkeys, Zimbardo's prison roleplaying, and Milgram's shock test led to the implementation of rules
What are the purposes of an Institutional Review Board (IRB)?

approve research being conducted at their particular institution

require participants give informed consent after hearing the risks and procedures

require debriefing of participants afterward with results of research

ensure humane and ethical treatment of animal and human subjects
__________ psychology is practical and designed for real world application, while __________ psychology is focused on research of fundamental principles and theories.
Applied; basic