Experimental Design Flashcards
What is the example of a positive control the lecturer references?
In the case of testing the effects of a new medication relative to an old medication are being tested, the experimental group would take the new medication while the control group would take the old medication. This control group is an example of positive control.
What is the example of a negative control the lecturer references?
In the case of testing the effects of a medication relative to no medication, the control group is negative because they receive nothing, only a placebo.
What is a historical control group?
Using a control group from studies in the past and comparing it to a current study
Why might someone use historical controls?
These controls may be used for ethical reasons.
What is an example of an ethically questionable control group?
Using a placebo medication on a group of people with an underlying medical condition (withholding treatment)
What are two drawbacks of correlational studies?
Third variables and reverse causation
What is reverse causation?
The possibility that B might cause A when it was assumed that A caused B
What is stratified sampling?
Sampling according to subgroups present within a population
What is a benefit to stratified sampling?
This sampling method may help to account for a third variable that may be interacting with the experiment variable (ie age)
what is pseudoreplication?
To treat two data points that are not independent as independent.
what is statistical power?
the probability of rejecting the null hypthesis
How can statistical power be increased?
Changing exp design, increasing sample size, reducing error from measurement and environmental factors, use more uniform experimental material, increase effect size
what is a factorial experiment?
When more than two variables are being manipulated and their effects observed in an experiment.
what does it mean to have a blocked experimental design?
to separate a sample based on a factor or factors believed to have an effect on the variable being measured
what is a within subject design?
a design where the effects of different treatments on an individual are measured at different times
