Question 12.137

cardiac

21. Researchers at Harvard measured the cardiac output in liters per minute of patients involved in a cardiogenomics study. A random sample of eight patients is summarized here. Use level of significance to do the following.

Test for interaction.
If appropriate, test whether cardiac output differs between those who have hypertension (high blood pressure) and those who do not.
If appropriate, test whether cardiac output differs between the genders.

	Factor A: Hypertension
	yes		No
Female	1.90	1.68	2.70	4.20
Male	2.60	2.20	4.30	5.50

12.4.21

(a) : There is no interaction between hypertension (Factor A) and gender (Factor B). : There is interaction between hypertension (Factor A) and gender (Factor B). Reject if the . The , which is not ; therefore we do not reject . There is insufficient evidence of interaction between hypertension (Factor A) and gender (Factor B) at level of significance . (b) : There is no hypertension (Factor A) effect. That is, the population means do not differ by whether or not the person has hypertension. : There is a hypertension (Factor A) effect. That is, the population means do differ by whether or not the person has hypertension. Reject if the . The , which is ; therefore we reject . There is evidence for a hypertension (Factor A) effect. Thus we can conclude at level of significance that there is a significant difference in mean cardiac output between patients who have hypertension and patients who don't. (c) : There is no gender (Factor B) effect. That is, the population means do not differ by gender. : There is a gender (Factor B) effect. That is, the population means do differ by gender. Reject if the . The , which is not ; therefore we do not reject . There is insufficient evidence for a gender (Factor B) effect. Thus we can conclude at level of significance that there is no significant difference in mean cardiac output between females and males.