A pulmonary researcher wants to investigate if smoking affects the lung capacity. They include 1,000 participants into 4 groups: non-smokers, light smokers, medium smokers, and heavy smokers. The lung capacity is measured by FEF (forced expiratory flow) in Liters per second. Assume the groups have constant variance.

1.What are the variable(s) in the study? (include units)

2.What is the level of measurement of the variable(s)? (Nominal, Ordinal, Continuous)

3.If there are groups are they related in any way?

4.What statistical test is most appropriate to use in analyzing the data given the information provided.