You have to draw a mathematical spatial axes .in order to judge is it right or not .. well you have to draw the crest and trough both of 1 cm in length and the total wavelength (same phase on the wave of 2 cm ) something like this
Answer:
Double blind experiment
Explanation:
It is an experimental method , which helps to avoid any impartiality and any error due to biasing .
The experiment give rise to very accurate results , which is very important for any experiment .
Hence , the new director Margaret , need to design a set of double - blind experiments.