Refer to the study described in Exercise 3.39.

a. Why would a time series plot be inappropriate for these data? What would a time series plot suggest about the mentoring trend for clinical psychology graduate students and for experimental psychology graduate students?

b. For four time points—1945–1950, 1965, 1985, and 1996–1998—the mentoring rates for clinical psychology graduate students were 48.00, 56.63, 47.50, and 62.31, respectively. For experimental psychology graduate students, the rates were 78.26, 57.14, 57.14, and 78.79, respectively. How does the story we see here conflict with the one that we developed based on just two time points?