Chapter 3 Flashcards
variable
- anything that can vary
measured variable
- observed and recorded
manipulated variable
- controlled
- by researcher
constant
- something that doesn’t change
- could potentially vary but only has one level in the study
Variables must have 2 levels (values). What does this mean?
ex. “most students don’t know when news is fake”
levels: knowing when news is fake and not knowing when news is fake
why can some variables only be measured and not manipulated?
- some variables are simply out of the researchers control
- can’t change age, height, etc.
- sometimes it would be unethical to manipulate certain variables (ex. making a group smoke) would be harmful to participants
how can some variables be both measured and/or manipulated?
- ex. mood
- probably wouldn’t do both in one study
what does it mean to operationalize a concept?
- turn it into a measured or manipulated variable
construct, conceptual variable
- name of the concept being studied
- ex. “satisfaction with life”
Conceptual definition
- a careful, theoretical definition of the construct
ex:
construct “satisfaction with life”
conceptual definition “a person’s cognitive evaluation of his or her life”
operational definition, operationalization
- how the construct is measured or manipulated in an actual study
- ex. questionnaires, observations, etc.
claim
- argument someone is trying to make
Frequency claims
- involve 1 variable
- describe a particular level or degree of a single variable
- trying to describe the 1 measured variable
- ex. 41% of…
Association claims
- one level of a variable is likely to be associated with a particular level of another variable
- supported by studies that have at least 2 measured variables (correlational studies)
- variables that are associated are said to correlate
association claims
positive association
- usually represented on a scatterplot
- as 1 variable increases (or decreases), the other does too
association claims
negative association
- can’t come up with a theme for how the variables are correlated
- when 1 v goes up, the other goes down (and v/v)
- slope downwards
causal claim
- arguing that one variable is responsible for changing the other
- at least one manipulated, one measured
What 3 criteria must causal claims satisfy?
1) must establish that the 2 variables are correlated
2) must show that the causal variable came first and the outcome variable came later
3) it must establish that no other explanations exist for the relationship
validity
- the appropriateness of a conclusion or decision
- reasonable, accurate, justifiable
construct validity
- how well a conceptual variable is operationalized
- must ensure that each variable has been measured reliably
generalizability
- how well did researchers choose their participants and how well do they represent the intended population
external validity
- how well the results of a study generalize or represent people or contexts besides those in the original study
statistical validity
- how well the numbers support the claim
- extent to which a study’s statistical conclusions are precise, reasonable and replicable
evaluating statistical validity
point estimate
- a single estimate of some population value (percentage, correlation, or a difference) based on data from a sample
confidence interval
- a given range indicated by a lower and upper value that is designated to capture the population value for some point of estimate
- ex. a contractor gives you a price range for your repairs. It could cost less or more but it will be in that range
internal validity
- ensures there are no alternative explanations for cause + effect
covariance
- the extent to which two variables are observed to go together
- established by the results of a study
interrogating causal claims
temporal precedence
- method was designed so that the causal variable clearly comes first in time, before the effect variable
- ex. “pretending to be batman helps kids stay on task” - the study must show that pretending to be batman came before staying on task
interrogating causal claims
internal validity (third-variable criterion)
- a study’s ability to eliminate alternative explanations for the association
experiment
- at least one variable is manipulated and the other is measured
independent variable
- manipulated variable
dependent variable
- measured variable
what are the 3 criteria for a causal claim?
1) covariance
2) temporal precedence
3) internal validity
