Explanatory or response? For each of the following scenarios, classify each of the pair of variables as explanatory or response or neither. Give reasons for your answers. (a) Whether or ot a person likes to sing and whether or not a person likes to dance. (b) The number of pages in a textbook and the cost of a new copy of the textbook. c) The number of alcoholic drinks consumed and the blood alcohol content. (d) In a study of adolescents, the dose of vitamin D given each day for a year (50, 100, or 200 international units) and the change in total bone mineral content from the beginning of the study to the end of the study.

The following is the classification of each pair of variables into two categories, namely explanatory and response, based on the relation between the variables:

(a) Whether or not a person likes to sing and whether or not a person likes to dance - Explanatory: There is no direct relation between the choices made by the person but it can be explained why he likes or does not like either of two or both.

(b) The number of pages in a textbook and the cost of a new copy of the textbook - Response: The cost of the book is dependent on the pages in it as each page bears some cost.

(c) The number of alcoholic drinks consumed and the blood alcohol content - Response: The blood alcohol content would keep increasing as long as alcohol is consumed.

(d) In a study of adolescents, the dose of vitamin D given each day for a year (50, 100, or 200 international units) and the change in total bone mineral content from the beginning of the study to the end of the study - Response: The amount of vitamin D would reflect as more in the adolescents that were administered higher dosages of vitamin D.