1. Decide how to model the variable in question in the following scenarios.
a. You measure reaction times for participants to process different words and want
to model that as a function of how often a person plays video games (fixed
effect). Should you include participant as a random intercept, random slope, or
neither?
b. You measure pitch of a speaker’s voice (outcome variable) and want to model
that as a function of whether they’re talking to a cat or a dog (fixed effect). You
have each participant speak to a cat, and then to a dog. Should you include
participant as a random intercept, random slope, or neither?
c. You measure duration (outcome variable) of a speaker saying a variety of words
of different lengths. You want to model duration as a function of number of
syllables (fixed effect). Should you include word as a random intercept, random
slope, or neither?
d. You measure performance on a picture recognition task (outcome variable =
overall score on the task) and want to model that as a function of age. Should
you include participant as a random intercept, random slope, or neither?
e. You measure ratings of different sentences (outcome variable) when they’re
spoken slowly and when they’re spoken quickly (fixed effect). You also have a
variable for sentence – should you include that as a random intercept, random
slope, or neither?