16. According to the US Department of Labor, the mean hourly wage in 1994 was $15.71 for a college graduate and $9.92 for a high school graduate. In 1979, the means (in 1994 dollars) were $15.52 for college graduates and $11.23 for high school graduates.

a) Construct a 2x2 table to display the results.

b) Compare the differences between 1994 and 1979 (i) for college graduates. (ii) for high school graduates. Is there interaction? Explain.

c) Show a set of four means that would display an absence of interaction.