According to "Films and Hormones," "researchers at the University of Michigan report that the male hormone [testosterone] rose as much as 30% in men while they watched The Godfather, Part II. Love stories and other ‘chick flicks' had a different effect: They made the ‘female hormone' progesterone rise 10% in both sexes. But not all films will make you more aggressive or romantic. Neither sex got a hormone reaction from a documentary about the Amazon rain forest."3 This study involved four variables: testosterone, progesterone, type of film, and gender.
a. Classify the variable for testosterone as being quantitative or categorical, and as explanatory or response. If it is categorical, tell how many possible values it can take.
b. Classify the variable for type of film as being quantitative or categorical, and as explanatory or response. If it is categorical, tell how many possible values it can take.
c. Classify the variable for gender as being quantitative or categorical, and as explanatory or response. If it is categorical, tell how many possible values it can take.