Answer the questions, using complete sentences.
a. What is extrapolation and why is it a bad idea in regression analysis?
b. How is the coefficient of determination related to the correlation, and what does the coefficient of determination show?
c. When testing the IQ of a group of adults (aged 25 to 50), an investigator noticed that the correlation between IQ and age was negative. Does this show that IQ goes down as we get older? Why or why not? Explain.