Question: 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.