Does ginkgo improve memory? The law allows marketers of herbs and othernatural

QUESTION:

Does ginkgo improve memory? The law allows marketers of herbs and other natural substances to make health claims that are not supported by evidence. Brands of ginkgo extract claim to improve memory and concentration. A randomized comparative experiment found no evidence for such effects.3 The subjects were 230 healthy people over 60 years old. They were randomly assigned to ginkgo or a placebo pill (a dummy pill that looks and tastes the same). All the subjects took a battery of tests for learning and memory before treatment started and again after six weeks.

(a) Following the model of Figure 9.3, outline the design of this experiment.

(b) Use the Simple Random Sample applet, other software, or Table B to assign half the subjects to the ginkgo group. If you use software, report the first 20 members of the ginkgo group (in the applets Sample bin) and the first 20 members of the placebo group (those left in the Population hopper). If you use Table B, start at line 103 and choose only the first 5 members of the ginkgo group.