Chapter 2 Flashcards
empiricism
the belief that accurate knowledge can be acquired through observation
scientific method
a procedure for using empirical evidence to establish facts
theories
hypothetical explanations of natural phenomena
hypothesis
falsifiable prediction made by a theory
empirical method
a set of rules and techniques for observation
operational definition
description of a property in measurable terms
construct validity
the extent to which a videocamera aimed at a face adequately characterizes the property (property of an operational definition)
power
a detector’s ability to detect the presence of differences or changes in the magnitude of a property
reliability
a detector’s ability to detect the absence of differences or changes in the magnitude of a property
demand characteristics
those aspects of an observational setting that cause people to behave as they think someone else wants or expects
naturalistic observation
a technique for gathering scientific information by unobtrusively observing people in their natural environments
observer bias
tendency for observers’ expectations to influence both what they believe they observed and what they actually observed
double-blind study
a study in which neither the researcher nor the participant knows how the participants are expected to behave
population
complete collection of people (eg. population of Canada, population of human beings)
sample
a partial collection of people/animals/things drawn from a population
frequency distribution
a graphic representation showing the number of times in which the measurement of a property takes on each of its possible values
normal distribution
a mathematically defined distribution in which the frequency of measurements is highest in the middle and decreases symmetrically in both directions (Gaussian)
mode
the value of the most frequently observed measurement
mean
the average value of all the measurements
median
value that is in the middle
range
value of the largest measurement in a frequency minus the value of the smallest measurement
standard deviation
how each of the measurements in a frequency distribution differs from the mean
variable
properties that can take on different values
correlation
variations in the value of one variable are synchronized with variations in the value of the other
correlation coefficient
mathematical measure of both the direction and strength of correlation (r)
natural correlation
the correlations we observe in the world around us
third-variable problem
the natural correlation between two variables cannot be taken as evidence of a causal relationship between them because a third variable might be causing them both
experimentation
a technique for establishing the causal relationship between variables
manipulation
technique for determining the causal power of a variable by actively changing its value
independent variable
the variable that is manipulated in an experiment
dependent variable
variable that is measured in an experiment
self-selection
a problem that occurs when anything about a participant determines the participant’s condition
random assignment
a procedure that assigns participants to a condition by chance
internal validity
an attribute of an experiment that allows it to establish causal relationships
external validity
an attribute of an experiment in which variables have been operationally defined in a normal, typical, or realistic way
case method
a procedure for gathering scientific information by studying a single individual
random sampling
a technique for selecting participants that ensures that every member of a population has an equal chance of being included in the sample
replication
an experiment that uses the same procedures as a previous experiment but with a new sample form the same population
type I error
when researchers conclude that there is a relationship between two variables when in fact there is not
type II error
when researchers conclude that there is not a relationship between two variables when in fact there is
informed consent
a verbal agreement to participate in a study made by an adult who has been informed of all the risks that participation may entail
debriefing
verbal description of the true nature and purpose of a study
