I’ll mark the Brainliest :) A researcher would like to study the relationship between average fuel economy (measured in miles per
gallon) and fuel type (premium, regular unleaded, and E85). He randomly selects 90 vehicles of various
makes and models, including compact cars, full-size cars, and trucks. All of the selected vehicles have
been driven less than 6,000 miles before the experiment.
a) Does this experiment use a control group? Explain.
b) Suppose the researcher would like to use a completely randomized design. Explain how the
researcher should assign the 90 vehicles to the three fuel types.
c) An advisor to the researcher suggests using a randomized block design. Should the researcher
block on type of vehicle (compact cars, full-size cars, and trucks) or number of miles previously
driven (0–2,000 miles; 2,000–4,000 miles; and 4,000–6,000 miles)? Explain your choice of
blocking variable