  Prior research has shown that physics students often think about experimental
procedures and data analysis very differently from experts. One key framework
for analyzing student thinking has found that student thinking is more
point-like, putting emphasis on the results of a single experimental trial,
whereas set-like thinking relies on the results of many trials. Recent work,
however, has found that students rarely fall into one of these two extremes,
which may be a limitation of how student thinking is evaluated. Measurements of
student thinking have focused on probing students' procedural knowledge by
asking them, for example, what steps they might take next in an experiment. Two
common refrains are to collect more data, or to improve the experiment and
collect better data. In both of these cases, the underlying reasons behind
student responses could be based in point-like or set-like thinking. In this
study we use individual student interviews to investigate how advanced physics
students believe the collection of more and better data will affect the results
of a classical and a quantum mechanical experiment. The results inform future
frameworks and assessments for characterizing students thinking between the
extremes of point and set reasoning in both classical and quantum regimes.
