Mark Grrshon, owner of a musical instrument distributorship, thinks that demand for guitars may be related to the number of television appearances by the popular group Maroon 5 during the previous month. Mark has collected the data shown in the following table:
a) Graph these data to see whether a linear equation might describe relationship between the group's television shows and guitar sales
b) Use the least-square regression method to derive a forecasting equation
c) What is your estimate for guitar sales if Maroon 5 performed on TV nine times last month?
d) What are the correlation coefficient (r) of determination (r2) for this model, and do they mean?