Consider the following linear regression model:

     a) What does y and x₁, x₂, . . . . x_k represent?

     b) What does β_o, β₁, β₂, . . . . β_k represent?

     c) What does the error term € describe?

The shares of the U.S automobile market held in 1990 General Motors, Japanese manufacturers, Ford, Chrysler and other manufacturers were, respectively 36%, 26%, 21%, 9%, and 8%. Suppose that a new survey of 1,000 new-car buyers shows the following purchase frequencies:

              GM (391, Japanese (202), Ford (275), Chrysler (53), Other (79)

     a) Show that it is appropriate to carry out a chi-square test using these data.

     b) Test to determine whether the new car market shares differ from those of 1990. Use α = 0.05.