Brucellosis is a reproductive disease in cattle and is very prevalent in some areas in the South. You would like to determine whether a cow's vaccination history is related to whether or not brucellosis occurs.

There are a number of factors relevant to an animal's vaccination history that are important in the prevention of brucellosis. These factors include: the Type of vaccination (vaccine A, vaccine B, vaccine C, or no vaccine), the Location on the animal where the shot is given (subcutaneous, interdermal, or conjunctival), the Number of shots the animal receives, and the Age at which the first shot is given.

(A). Is this an observational or experimental study?

(B). What is the type ofresponse variablecollected in the study, and what is the statistic(s) used to describe this type of response variable?

(C). Does this study have a factorial scale? If so, what is the factorial scale?