Travel and Transportation
The Channel Tunnel, or Chunnel, is a 31.4-mile railroad tunnel beneath the EnglishChannel between Folkstone, Kent, in England and Coquelles in France. To ensure passenger safety, engineers selected the35 deepest areas in the tunnel and measured the pressure on each section.
a. Is this an observational or an experimental study?
b. What is the variable of interest?
c. Is this sample random? If so, justify your answer. If not, describe a technique to obtain a random sample.