If the variability of the returns on large-company stocks were to increase over the long-term, you would expect which of the following to occur as a result?
I. decrease in the average rate of return
II. increase in the risk premium
III. increase in the 68 percent probability range of the frequency distribution of returns
IV. decrease in the standard deviation
II and IV only
I only
IV only
I and III only
II and III only