The LM statistic requires estimation of the unrestricted model only.

The ceteris paribus assumption is important in economics because

A) all empirical data are equal. B) it would be impossible to relate the changes in one variable to another variable without holding other variables constant. C) economic data move very slowly over time and so they can always be considered constant. D) models are always complex and require as many variables as possible.

Which of the following would most likely be considered complements?

A) butter and margarine B) rental cars and taxis C) plastic wrap and aluminum foil D) tennis rackets and tennis balls