Erratum to: Math Ed Res J

https://doi.org/10.1007/s13394-017-0209-3

The original version of this article unfortunately contained a mistake.

In Fig. 3, the centrally located characters “C, c, a, m” were included in error and form no part of the intended diagram. The correct version of Fig. 3 is given below:

Fig. 3
figure 1

Classroom configuration showing video camera sight lines

The original article was corrected.