Presentation 2 : Experimental Design Flashcards
Define confounding variables
Variables that can potentially distort the relationship between the IV and DV
-> contribute to bias
Define Target Population
the group of people to which the findings of the study are expected to be generalized. A group of people who can represent an entire population
Define generalize
a measure of how useful the results of a study are for a broader group of people or situations
Define Random Sampling
The ideal approach to sampling the representative. Every member of the target population has an equal chance of becoming part of the sample.
Define Stratified sampling
researcher chooses the characteristics of the target population wished to be studied then chooses the sample to best reflect those desired characteristics.
Define Convenience (opportunity) sampling
The researcher recruits participants that are most easily available.
Define Self-selected sampling
The researcher recruiting volunteers.
Define Experimental Design
The organization of groups and conditions in an experiment
Define Independent measures design
involves randomly allocation (placement) of participants from you sample group into the experimental group and the control group. Then manipulate the experimental conditions and compare the dependent variable in the two groups.
Define Matched pairs design
similar to independent measures, the researcher purposefully matches participants to form groups.
Define Repeated measures design
method used when the goal is to compare conditions rather than groups of participants. The sample group of participants is exposed to two (or more) conditions, and the conditions are compared.
Define Construct validity
characterizes the quality of operationalization. Remember operationalization is how a researcher applies a measurable quality to a behavior.
Define Internal validity
characterizes the methodological quality of the experiment. Internal validity is high when confounding variables have been controlled and high certainty the IV caused the change in DV.
Define External validity
characterizes how the results of the research can be generalized (related) back to the population as a whole
Define Selection Bias
Occurs when groups are not equivalent from the start of the experiment. (IV)
Define History Bias
When outside events happen to participants in the course of an experiment. (IV)
Define Maturation Bias
During the experiment participants go through natural
development, such as fatigue or simply growth. (IV)
Define Experiment bias
occurs when the experimenter influences the
results unintentionally. (IV)
Define Testing effect
The first measurements of the DV may affect the
second (and other) measurements.
Define Instrumentation
This effect occurs when the instrument measuring the DV changes slighting between measurements. Such as an observer measuring a behavior.
Define Regression to the mean
This occurs when the resulting DV’s measurement is extreme (either too low or high).
Define Experimental mortality
refers to the fact that some participants
leave or drop out from the experiment, especially if not random.
Define Demand characteristics
this situation happens when participants understand the purpose of the experiment and change their behavior to fit the experiment.
Define Quasi-experiments
“Quasi” is a prefix meaning “almost”. In these experiments the groups are not made randomly and are grouped based upon pre-existing differences such as age, gender, culture and/or occupation.
Define Field experiments
Experiments that are conducted in real life settings. The researcher manipulates the IV, but the participants are in their natural setting.
Define Natural Experiments
conducted in participants natural environment, but here the researcher has no control over the IV – the IV occurred naturally.
