Types of experiments - randomized and quasi Flashcards
(29 cards)
one shot
-quasi
-Only one group at single point in time
-No control or comparison group
-Run an ad campaign, measure sales
one group pretest posttest
-quasi
-Only one group but tested prior to and after “treatment”
- No control or comparison group
-Measure sales, run ad campaign, measure sales again
static group
-quasi
-Comparison between one group that got a treatment and one that
hasn’t
-Measuring differences between 2 groups of people
-Exercisers, non-exercisers, dependent variable is resting heart rate
before and after with control
-randomized
-Random assignment to either experimental or control group, everyone gets a pretest, experimental starts program exercise, then measure resting heart rate again
solomon four group
-randomized
-Most robust design but harder to implement due to time and
resource constraints.
-4 groups randomly assigned – 2 groups get a pretest, 2 groups do not, 2 groups get a treatment, 2 groups do not, and everybody gets a posttest
after only with control
-randomized
-When researchers want to eliminate testing effects, so only a
posttest measurement is done
-Randomly assigned to experimental or control group, then measure some outcome
-best one
quasi experiment
no random assignment to conditions
Threats to internal validity and control.
true experiment
random assignment to conditions
random assignment
-For internal validity
- To establish control in experiments
random sampling
-For external validity
-To be able to generalize from a sample to a larger population
How to establish a cause and effect relationship:
-Covaration
-Temporal precedence
-Internal validity
covariation
(correlation) positive or negative
temporal precedence
the cause precedes the effect
internal validity
★refers to our ability to rule out plausible alternative explanations for the relationship★
threats to internal validity
-History
-Maturation
-Testing (two types)
-Instrumentation
-Selection
-Mortality
history
occurs outside the experiment. Has an effect on the dependent variable.
maturation
refers to our participants getting older, smarter, wiser, growing up
testing
(interactive testing): The Practice, practice at time 1 gets you to do better at time 2.
instrumentation
any change from O1 to O2 is due to the measuring instrument
selection
refers to whether or not if we can randomly assign people to control
mortality
Mortality: people dropping out of the study. Cannot force them.
questionaire design
-demographics last
-satisficing v. optimizing
-funnel technique
-grice’s norms of conversation
-leading/loaded questions
-ranking v. rating
-types of questions
-open v. closd
satisficing/optimizing
people tend to satisfice → typically cognitively lazy
Weak and strong forms of satisficing
Want them to optimize
funnel technique
Start with broad questions, move to more specific questions