Chapter 4, Problem T4.9SPT

To determine

To select the best option from the multiple choice question according to the given question.

Answer to Problem T4.9SPT

Option (c) is correct.

Explanation of Solution

There are four treatment groups using two explanatory variables: length ( $30\text{ or }60$ seconds) and repetition ( $1\text{ or }3$ ).

All subjects were randomly assigned to one of the four groups, thus it is a completely randomized design. Thus, we have that option (d) is the correct option i.e. there is a completely randomized design with two explanatory variables (factors).