Suppose That a Researcher Wishes to Test for Calendar (Seasonal)

Multiple Choice

Suppose that a researcher wishes to test for calendar (seasonal) effects using a dummy variables approach. Which of the following regressions could be used to examine this?
(I) A regression containing intercept dummies
(ii) A regression containing slope dummies
(iii) A regression containing intercept and slope dummies
(iv) A regression containing a dummy variable taking the value 1 for one observation and zero for all others

A) (ii) and (iv) only
B) (i) and (iii) only
C) (i) , (ii) , and (iii) only
D) (i) , (ii) , (iii) , and (iv) .