Menopause

Researchers studied the herb black cohosh as a treatment for hot flashes caused by menopause. They randomly assigned 351 women aged 45 to 55 who reported at least two hot flashes a day to one of five groups:

(1) black cohosh,

(2) a multiherb supplement with black cohosh,

(3) the multiherb supplement plus advice to consume more soy foods,

(4) estrogen replacement therapy, or

(5) receive a placebo. After a year, only the women given estrogen replacement therapy had symptoms different from those of the placebo group. [Annals of Internal Medicine 145:12, 869 897]

a) What kind of study was this?

b) Is that an appropriate choice for this problem?

c) Who were the subjects?

d) Identify the treatment and response variables.