The format for the 83 items was
multiple-choice plus explanation. The response to an item was only coded as using a particular
misconception when a clear answer and a consistent reason were given. The information obtained
in interviews was used in analysing students’ misconceptions but not used in counting the number
of students having the misconception. Therefore, given the conservative nature of the coding the
data presented here should be a lower bound for the actual number of students with a
misconception.