Exam 3 study guide Flashcards
interaction effect
occurs when the effect of one IV depends on the level of another IV
2 types of interaction effects
crossover interaction
- “it depends”
- graph makes a X
spreading interaction
- “only when”
- graph is 75 degree angle facing to the left
how many cells in a 2x2 factorial design
4 cells
participant variables
any demographic characteristics, things the experimenter cannot manipulate
when the graph shows two parallel lines, this represents …
no interaction effect
how do we know there is a large effect shown in a 2x2 factorial
calculate the marginal means for each level of the 2 IV’s (should end up with 4 means) and then compare the marginal means in each IV
interaction effect calculation
- find marginal means (a, b, c, d)
- subtract marginal means in each IV (a-b =x, c-d=y)
- find the difference within IV’s (x-y)
when a study shows both a main effect and an interaction, the interaction is almost always…
more important
you can have ____________ main effects and a ________ interaction effect
non-significant; significant
3 factorial variations
independent-groups factorial design
within-groups factorial designs
mixed factorial designs
independent-groups factorial design
both IVs are studied as independent groups aka between subjects
each cell of the 2x2 has a different group of participants
within-groups factorial design
both IVs are manipulated within groups
only one group of participants in all four cells
mixed factorial designs
one IV is manipulated as independent-groups and the other is manipulated within-groups
2 cells share the same group while the other two cells share a different group
the same group cells are for the independent-groups IV
for a 2x2x2 factorial, there would be …
3 main effects
3 two-way interactions
1 three-way interaction
2 ways to identify factorial designs in empirical journal articles
the method section will describe the study
- __x__x__
the results section will examine whether the main effects and interactions were significant
2 ways to identify factorial designs in popular press articles
look for “it depends” or “only when” to highlight interaction
look for participant variables (age, gender, ethnicity, etc.)
bivariate correlations
associations that involve exactly two variables
ex. level of happiness and days spent on vacation
think quantitative or categorical
cohen’s guidelines
.10 or -.10 = small, or week
.30 or -.30 = medium, or moderate
.50 or -.50 = large, or strong
mean
arthmetic average
t test
a statistic to test the difference between two group averages
do you know how to plot points on a graph then determine if the correlation is positive, negative, or neither?
obviously
construct validity: ask about the construct validity of _____ variable
each
effect size
describes the strength of an association
statistical validity
_____ effect sizes give more accurate predictions
larger