chapter 2 Flashcards
research methods and measurement
empiricism
the conviction that accurate knowledge of the world can be acquired by observing it
scientific method
a procedure for using empirical evidence to establish facts
theory
an explanation of a natural phenomenon
hypothesis
an explanation of a natural phenomenon
empirical method
a set of rules and techniques for observation
operational definition
a description of a property in measurable terms
construct validity
a feature of operational definitions whose specified operations are generally considered good indicators of the specified properties.
power
a detectors ability to detect the presence of differences or changes in the magnitude of a property
reliability
a detectors ability to detect the absence of differences or changes in the magnitude of a property
demand characteristics
aspects of an observational setting that cause people to behave as they think someone else wants or expects
naturalistic observation
a technique for gathering info by unobtrusively observing people in their natural environments
observer bias
the 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
a complete collection of people
sample
a partial collection of people drawn from a population
frequency distribution
a graphic representation showing the number of times that the measurement
normal distribution
a mathematically defined distribution in which the frequency of measurements is highest in the middle and decreases symmetrically in both directions
mode
the value of the most frequently observed measurement
pros: works well with normal frequency data, can produce sensible values
Cons: has low sampling stability, may not exist for some data, only works for symmetric unimodal distributions
mean
the average value of all the measurements
pros: best sampling stability, works with many statistical methods
cons: value may not exist in real world, assumes data is on an interval measurement scale, not robust to extreme values
median
value that is in the middle
pros: robust to extreme values
cons: does not work well with a lot of common statistical methods, has fairly low sampling stability
range
the value of the largest measurement in a frequency distribution
standard deviation
a statistic that describes how each of the measurements in a frequency distribution differs from the mean
only works for symmetrical unimodal distributions
variable
a property that can have more than one value
correlation
a relationship between variables in which variations in the value of 1 variable are synchronized with variations in the value of the other
correlation coefficient (r)
a mathematical measure of both the direction and strength of a correlation. symbolized by the letter r.
r=0 (no correlation)
r= 1 (perfect positive correlation )
r= -1 (perfect negative correlation)
natural correlation
a correlation that is observed in the natural world
third variable problem
the fact that the natural correlation between 2 variables cannot be taken as evidence of a casual relationship between them because a 3rd variable might be causing them both.
experimentation
a technique used for establishing the casual relationship between variables
manipulation
a technique for determining the casual power if a variable by actively changing its value
independent variable
the variable that is manipulated in the experiment
dependent variable
the variable that is measured in the experiment
self selection
a problem that occurs when anything about a participant determines the value of the independent variable to which the participant was exposed
random assignment
a procedure that assigns participants to conditions by chance
internal validity
an attribute of an experiment that allows it to establish casual relationships
external validity
an attribute of an experiment in which variables have been operationally defined in a representative way
case method
a procedure for gathering scientific info 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 sues the same procedures as a previous experiment but with a new sample from the same population
type 1 error
an error that occurs when researchers conclude that there is a casual relationship between 2 variables when there in fact is not
type 2 error
an error that occurs when researchers conclude that there is not a casual relationship between 2 variables when there in fact 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.
steps of scientific method
- identify the question of interest
- gather relevant info and formulate a testable hypothesis
- design a study that can test the hypothesis
- analyze the data and draw tentative conclusions
- report the findings and ask further questions
falsifiability
a characteristic of a hypothesis if it is capable of being disproved
deductive argument/ statement
an argument in which the conclusion necessarily follows from the premises. i.e. it is impossible for the conclusion to be false given that the premises are true
inductive argument/statement
an argument in which it is improbable that the conclusion is false given that the premises are true
central tendency
the most typical value of a data set. 3 common measures: mode, median, and mean
negative skew
skewed left. long tail points left.
mean< median< mode
symmetrical
symmetrically normal. tails are balanced
mean=median=mode
positive skew
skewed right. long tail points right
mode<median<mean
research ethics board (REBs)
a committee of researchers and officials at an institution charges with the protection of human research participants
Canadian council on animal care (CCAC)
the three R’s:
replacement: methods to avoid or replace use of animals
reduction: strategy to reduce amount of animals used
refinement: modification of experimental procedures to minimize distress
anecdote
a short, often interesting or amusing, personal experience.
reliability
consistency of measurements
test retest reliability
when a test/ measure is readministered it should produce the same result as when it was administered the 1st time
interobserver reliability
two or more people using the same test/measure should arrive at the same conclusion
blinding
a subject is not aware of the group ( experimental or control) they are in
confounding variable
any difference between the experimental and control groups other than the independent variable
statistical significance
p-value is less than 0.05.
control vs experiment groups
the experimental group receives the treatment being tested, while the control group does not
confirmation bias
the tendency to seek out info that supports our hypothesis and deny, ignore, or distort info that contradicts it.
availability heuristic
when you estimate the likelihood of an occurrence bases on the ease which it comes to mind.
