Stats and research Flashcards
idiographic
single subject
nomothetic
group studies
AB design problem
threat of history - hard to tie intervention to change
ABAB design problems
protects against threat of history
threat of failure to return to baseline
ethics of stopping intervention
analogue research vs. clinical trial
less generalizability vs methodological compromise
cross sectional design problem
cohort effect
longitudinal problems
expensive, attrition rate
cross-sequential research
combine longitudinal and cross sectional
proportional sampling
randomly selected in proportion to representation
systemic sampling
every nth random
cluster sampling
naturally occurring groups, but everyone within the groups
Threats to internal validity
anything other than IV causing change in DV (history, maturation, test practice, instrumentation)
Solomon four-group design
Corrects for test practice
pre/post vs. post only
intervention vs. no intervention
Instrumentation
threat to internal validity
change in observer or equipment resulting in change to DV. Correct with control group
Statistical regression/ regression to the mean
extreme scores get less extreme
manage with control group
selection bias
correct with random assignment
attrition/experimental mortality
problem if differential in group dropout rates
Compare groups who drop out with t tests
Diffusion
no-treatment group gets some treatment indirectly
Experimental expectations/ Rosenthal effect
Experimenter transmit clues. correct with experimenter blindness
Demand characteristics
features of procedures that suggest expectations to participants
John Henry effect/compensatory rivalry
control group work harder to compete with experimental group. Try to keep control and experimental group unaware of each other.
Threat to external validity
sample characteristics, stimulus characteriastics, contextual characteristics
Sample characteristics
diff between sample and pop
Stimulus characcteristics
features of study associated with intervention
Contextual characteristics
conditions in which intervention embedded. Reactive/Hawthorn effect
Threats to statistical conclusion validity
low power, unreliability, variability in procefures,. subject heternogeity.
positive skew
peak to left
neg skew
peak to right
standard error of mean
all possible means from random assignment groupings, how far they deviate from middle
Central limit theorem
Rejection region / region of unlikely value
area corresponds to
Type 1 error
mistakenly rejecting Ho
proportionate to alpha
Type 2 error
mistakenly adopt Ho
Inverse with alpha
Choosing based on DV
non-parametric if nominal/ordinal
parametric - t-test, anova
1+ DV - MANOVA