best fit line
a straight line on a scatterplot that best represents the data; it may or may not pass through some or all of the data points
case study
a research method which investigates a single subject in great detail
clinical observation
a diagnostic method in which a subject is watched for signs of mental illness
confounding variable
generally, something that affects the outcome of an experiment that had not been considered in the research design
control group
in an experiment, the subjects who are not subjected to the independent variable
correlation
a statistical relationship between two variables
correlation coefficient
the measurement of a statistical relationship between two variables
debriefing
giving research subjects a full explanation of the research at the end of the research project
dependent variable
what the experimenter measures at the end of an experiment
descriptive statistics
statistical information used to describe aspects of the data collected
double-blind
an experiment in which neither the experimenter or the subjects know which subjects are in the experimental or control groups
experiment
a research method in which a variable is manipulated in order to assess its effect on another variable
experimental group
in an experiment, the subjects who are subjected to the independent variable
generalization
the process of deriving a principle from a limited number of observations and applying more broadly
hypothesis
a prediction; an empirically testable proposition
illusory correlation
the perception of a relationship between variables where none really exists
independent variable
the variable manipulated by an experimenter
inferential statistics
methods that allow researchers to draw conclusions about a population from data derived from a small sample of the population
informed consent
voluntary agreement to participate in research by a subject who is aware of the risks and benefits of participating
mean
the arithmetical average of a set of numbers
median
the score that divides a distribution into two equal-sized halves
mode
the most common element in a set of data
naturalistic observation
a research method in which subjects are observed in their ordinary habitat
negative skew
a non-normal distribution with a long tail extending to the left has this
normal distirbution
also called Gaussian, this refers to a set of data whose graph is symmetrical and bell-shaped
null hypothesis
the statement that an experiment will find no difference between the experimental and control conditions
operational definition
a description of a variable in terms of the method in which it will be measured
percentile
the location of a score in a distribution such that its location describes the amount of the distirbution less than that score
placebo
an inert substance used with a control group in place of the active substance used with the experimental group, as, for example, in a drug test
population
all the members of a group friom which a sample may be drawn
negative correlation
a number between 0 and -1.0 that describes the relationship between two variables
positive correlation
a number between 0 and 1.0 that describes a relationship between two variables
positive skew
a non-normal distribution with a long tail to the right has this
random assignment
the process by which each member of the sample has an equal opportunity to be included in the experimental or control group
random sample
the process by which each member of the population has an equal opportunity to be included in the sample
range
in statistics, a measure of dispersion found by subtracting the smallest score from the largest in a distribution
replication
performing the essence of a research project again using different subjects
representative sample
this accurately reproduces the characteristics of the population from which it is drawn
sampling error
the extent to which a sample is not representative of the population
scatterplot
a method of graphing data involving two variables
single blind
an experiment in which the subjects, but not the experimenter, are unaware of which members are in the experimental or control groups
standard deviation
a measure of dispersion; the average distance from the mean of each data point
statistical significance
the degree to which a result cannot be attributed to chance
statistics
a branch of mathematics that uses data descriptively or inferentially to support scientific questions
survey
a research method in which members of a sample are asked about their opinions
theory
this organizes and summarizes observations and experiments and can be used to make predictions
critical thinking
its elements are: examine assumptions, discern bias, evaluate evidence, assess conclusions
scalable
a quality variables must have in a correlation; it means able to measured on a scale
false consensus
the tendency to overestimate the extent to which others share our beliefs
IRB
the body that must approve research projects in a university
case history
this could be a part of case study in which the clinician looks at the long-term experience of a patient
confederate
one who appears to be a participant in a study, but is actually working with the experimenter
confederate
examples of this are the "teachers" in Milgram's obedience studies or most of the participants in Asch's conformity studies
cross-sectional study
a research method in which the subjects belong to one of a number of different age-range groups
longitudinal study
a research method in which subjects are observed or tested over a long period of time - in some cases, over a lifetime
demand characteristic
any aspect of a research project that communicates to participants how they are expected to behave
evidence-based practice
using research results to inform clinical practice
descriptive research
methods of investigation that provide useful information about a phenomenon, but cannot be used to find correlations or cause-and-effect
empirical method
gaining information through observation, data collection, and logical reasoning
experimental bias
this occurs when the researcher's expectations or preconceptions affect the results of the research
external validity
the extent to which a research design actually reflects the real world situation it purports to address
external validity
Was Milgram's experiment an accurate reflection of the obedience expected of German soldiers? If not, his experiment can be said to lack ________________
internal validity
the extent to which changes in the dependent variable are the result of the independent variable
meta-analysis
a statistical method which allows a researcher to summarize results from many studies of a topic
placebo effect
this occurs when participant's expectations affect the outcome of a study, as, for example, when in a drug study those in the control group seem to exhibit the effects of the drug
participant bias
this occurs when subjects of a study alter their behavior according to how the think they should behave
third variable problem
occurs when a variable not considered in the research design affects the outcome of the research (i.e., a confounding variable)
hindsight bias
to claim after the fact that you could have predicted how an event occurred is evidence of this
sampling bias
this occurs when the process of choosing participants in a study is affected by prejudices or expectations of the researcher
5 terms for the way data in a study can be graphed when the data make a symmetrical graph
normal distribution, normal curve, bell curve, standard distribution, standard curve
trend line
another term for best fit line