Assumes that the data frames in the list have a non-empty set of shared variables. Among them at least either point.x
, point.y
or x
, y
defining the bullet holes. To be useful for functions analyzeGroup
or compareGroups
, the data frames should also have variables group
, distance
, aim.x
, aim.y
defining point of aim. If group
is missing, it is set to 1.