Physical Sciences The Air Liquide Company has developed a new deicing chemical for airplanes, consisting of glycol and several proprietary additives. The new chemical was designed to keep aircraft wings ice-free for a longer period of time. Ten typical Dehaviland commuter airplanes were obtained and randomly assigned to one of two groups: new chemical versus old chemical. Each plane was subject to constant icing conditions in a controlled environment and treated with one of the chemicals. The length of time until ice formed on the wings was recorded for each plane.
a. Is this an observational or an experimental study?
b. What is the variable of interest?
c. Describe a technique to randomly assign each plane to a chemical group.