Unit 320: Moderation, two dummy variables
In this assignment you will analyze linear models which include an interaction between two
dummy variables.
For this assignment, you will use the fictional dataset ‘swearing.sav’ again. Before doing any
analysis, make sure to (install and) load the packages tidyverse, foreign and broom and
import the dataset into the R environment.
Remember, in the (fictional) data set you can find information about the number of times
people (that made a new year’s resolution to swear less) sweared in a certain period of
time. Half of the participants received an app on their phone which informs them of their
swearing habits. The other half of the participants receive no information.
We only expect an effect of the app when the individual using the app is motivated to
reduce how much they swear. In other words, we expect that the effect of the app on
swearing depends on level of motivation.
Something that might motivate people to reduce swearing is whether they have children.
We will now look at a model with the following variables:
• Swearing: number of swear words the participant used during the week of the experiment
• App: variable which tells us whether the participant had an app which informed them of
their swearing.
• Children: dummy variable which tells us whether the participant has children under the
age of 12.
1. Draw the theoretical model using boxes and arrows.
Children
_
App Swearing
2. Give the (empty) linear equation for the population.
- Swearing = b0 + b1 x AppUse + b2 x Children + b3 x AppUse x Children
In this assignment you will analyze linear models which include an interaction between two
dummy variables.
For this assignment, you will use the fictional dataset ‘swearing.sav’ again. Before doing any
analysis, make sure to (install and) load the packages tidyverse, foreign and broom and
import the dataset into the R environment.
Remember, in the (fictional) data set you can find information about the number of times
people (that made a new year’s resolution to swear less) sweared in a certain period of
time. Half of the participants received an app on their phone which informs them of their
swearing habits. The other half of the participants receive no information.
We only expect an effect of the app when the individual using the app is motivated to
reduce how much they swear. In other words, we expect that the effect of the app on
swearing depends on level of motivation.
Something that might motivate people to reduce swearing is whether they have children.
We will now look at a model with the following variables:
• Swearing: number of swear words the participant used during the week of the experiment
• App: variable which tells us whether the participant had an app which informed them of
their swearing.
• Children: dummy variable which tells us whether the participant has children under the
age of 12.
1. Draw the theoretical model using boxes and arrows.
Children
_
App Swearing
2. Give the (empty) linear equation for the population.
- Swearing = b0 + b1 x AppUse + b2 x Children + b3 x AppUse x Children
