Exercise

# 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.

Instructions

**100 XP**

- Compute the
`length()`

of the`levels()`

of`chocolate$Subject`

.