Three brands of running shoes are each tested by 10 different runners.The amount of wear on the sole of the shoes is then measured.The objective is to determine if there is any difference among the three brands of shoes based on how long the soles last.The degrees of freedom for testing whether there is any blocking effect D₁ = 9 and D₂ = 18.

Question

Quizplus · Accepted Answer

The degrees of freedom for testing blocking effects depend on the number of levels for each factor and the number of replications within each cell. In this case, there are three levels for the brand factor (shoes), and 10 replicates within each cell (10 runners testing each shoe). Therefore, the degrees of freedom for testing blocking effect are (3-1)x(10-1) = 18. Since the given values for D₁ and D₂ are smaller than this value, it is true that there are blocking effects present in the experiment.

Three Brands of Running Shoes Are Each Tested by 10