In an experiment testing the effectiveness of five different advertisements for a new product in five separate markets, sales of the new product are recorded at the end of each week for eight weeks. Analysis of variance is used to investigate whether the advertisements are equally successful.
-The total number of degrees of freedom for the design is
A) 35.
B) 4.
C) 7.
D) 28.
E) 39.

Question

Quizplus · Accepted Answer

The total number of degrees of freedom for the design is calculated by subtracting 1 from the total number of observations. Since there are 5 markets, each observed for 8 weeks, there are 5*8=40 observations in total. Subtracting 1 gives 40-1=39 degrees of freedom.

In an Experiment Testing the Effectiveness of Five Different Advertisements