Chapter 4.2, Problem 74E

(a)

To determine

To find out what are the blocks in this experiment.

Answer to Problem 74E

The gender have to be the different blocks.

Explanation of Solution

The patients were male or female (gender), while there were randomly assigned to a therapy i.e. treatments.

Since the therapies are not characteristics of patient itself, the therapies cannot be the blocks for the patients because they were randomly assigned to the treatments.

The blocks cannot be the treatments but have to be the characteristics of the patients and thus the gender have to be the different blocks as the gender of the subject is a characteristics of the subject.

(b)

To determine

To explain why a randomized block design is preferable to a completely randomized design in this context.

Explanation of Solution

In this study, the patients were male or female (gender), while there were randomly assigned to a therapy i.e. treatments.

A randomized block design can group the subject into blocks which have a common characteristics and thus a randomized block design allow us to take into account the change of one or more extra variables.

A completely randomized design is only able to take into account the changes of the predictor variable.

(c)

To determine

To explain what advantages and disadvantages would this offer.

Explanation of Solution

An advantage of the study using $800$ males and zero females is that researchers can fixate on whether the drug is working in the males or not, which will consume less time and energy of them. A disadvantage of this case is that this makes it a non-block study and it is now impossible to determine if the drug works for all of mankind or just males. So this result can have biasness in the result.