Question

A market research company wishes to find out whether SFU students prefer brand A or brand B of instant coffee. A random sample of students is selected, and each one is asked to try brand A first and then brand B (or vice versa, with the order determined at random). They then indicate which brand they prefer.

(a) This is an example of

A. block design.
B. an observational study, not an experiment.  
C. a matched-pairs experiment  
D. stratified sampling design.

(b) The response variable here is

A. whether brand A or brand B is tried first.  
B. the identity of the student.
C. which brand they prefer.  
D. None of the above.

Answer 1

(a) Option (B) is the correct alternative. ( In an experiment, investigators apply treatments to experimental units. In an observational study, investigators observe subjects and measure variables of interest.)

(b) Option (C) is the correct alternative. ( response variable is the one whose value is predicted or its variation is explained by the explanatory variable. This is the outcome that is measured following manipulation of the explanatory variable)