How many people answered the chocolate suvey?
Before we fit a hierarchical model, we should know how many people answered the survey. The person who answered each question in the chocolate
data is identified by a number in the Subject
variable. We can find out how many people are described in the data by finding the number of levels of the subject variable. The chocolate
data is already loaded. levels()
returns a vector with the levels of a factor and length()
will tell us the length of the vector.
Cet exercice fait partie du cours
Choice Modeling for Marketing in R
Instructions
- Compute the
length()
of thelevels()
ofchocolate$Subject
.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
# Determine the number of subjects in chocolate$Subjects