In a randomized, controlled, double-blind study: select one:

a. experimental subjects are blind-folded when given the experimental treatment.
b. individuals will be assigned to an experimental or control group depending on whether they took part in a pilot study.
c. all experimental variables are held constant.
d. neither the experimenter nor the subject know whether the subject is in a control group or an experimental group.
e. all of the above.

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human x chromosome. the patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. they rarely live past their twenties. how likely is it for a woman to have this condition? a) women can never have this condition.b) one-fourth of the daughters of an affected man would have this condition.c) one-half of the daughters of an affected father and a carrier mother could have this condition.d) only if a woman is xxx could she have this condition.