Evaluation of two assumptions: single straight line, and single normal distribution.
Using graphical and statistical approaches, Laszlo Endrenyi and Mayank Patel describe methods that answer two frequently asked questions: 'Can the data be characterized by a single straight line, or should a more complex model be invoked?' and 'Do the observations follow a single normal distribution, or is there evidence for deviations from this assumption, including the possibility of bimodality?" These methods complement those addressed in a recent Principles article by Dick Barlow.
Endrenyi
L
L
Department of Pharmacology, University of Toronto, Ontario, Canada.
Patel
M
M
D012107:Research Design; D013223:Statistics as Topic