Question

Can a vegetarian or low-salt diet reduce blood pressure? Men with high blood pressure are

assigned at random to one of four diets: (1) normal diet with unrestricted salt; (2)

vegetarian with unrestricted salt; (3) normal with restricted salt; and (4) vegetarian with

restricted salt. This experiment has

1. one factor, the type of diet.
2. two factors, high blood pressure and type of diet.
3. two factors, normal/vegetarian diet and unrestricted/restricted salt.
4. three factors, men, high blood pressure, and type of diet.
5. four factors, the four diets being compared.

Short answer

Our required answer is option (c): two factors, normal/vegetarian diet and unrestricted/restricted salt.

Step-by-step solution

Given Information

We need to find out number of factors in experiment given to us. Experiment has four diets:

1. normal diet with unrestricted salt.
2. vegetarian with unrestricted salt.
3. normal with restricted salt.
4. vegetarian with restricted salt.

Explanation

Factors are variables whose levels are changed by the experimenter, and hence these variables are within his control.

Four diets given in experiment are:

• normal diet with unrestricted salt.
• vegetarian with unrestricted salt.
• normal with restricted salt.
• vegetarian with restricted salt.

We can see that we have either normal or vegetarian diet. So this can be considered as one of the factor. And we have also options between restricted and unrestricted salt that is second factor of our experiment.

So concluding we have two factors that are normal/vegetarian diet and unrestricted/restricted salt in our experiment.

Hence, option $c$is our required answer.