You expect that continued increases in the frequency with which customers are targeted with email advertisements will lead to customer frustration and a reduction in sales after a certain point (i. e. an inverted U relationship between Sales and number of email advertisements ( (#EmailAds)). Model A: Sales = a + b* #EmailAds
Model B: Sales=a+b* In(#EmailAds)
Model C Sales = a + b* #EmailAds + ct #EmailAds2
Model D: Sales = a +b #EmailAds + CtIn(EmailAds)
From the above models, which would be best to use for estimation:
A. Model B.
B. Model D.
C. Model D.
D. Model A