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 statistically significant evidence for such effects. The subjects were 350 healthy volunteers over 60 years old. They were randomly assigned to ginkgo of 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) The study was double-blind. Why is this important?

(b) If the results were statistically significant, can the results of this study be generalized to a larger population? Can cause-and-effect be inferred? Explain

(c) Explain why it is advantageous to use 350 volunteers in this study, rather than, say, 30 volunteers.

(d) Name two variables that were controlled in this experiment and why was it beneficial to control these variables?

Answer 1

Step-by-step explanation:

(a) The study being double-blind is important because it means that neither the subjects nor the researchers administering the treatment knew which subjects were receiving the ginkgo and which were receiving the placebo. This helps to prevent bias in the results, as it eliminates the possibility that the researchers could unintentionally influence the outcome by treating the groups differently.

(b) If the results were statistically significant, they could be generalized to a larger population with some degree of confidence, but this would depend on the specifics of the study design and the characteristics of the population in question. However, the study alone cannot establish cause-and-effect between ginkgo and improved memory, as other factors could be responsible for any observed differences between the treatment and placebo groups.

(c) Using 350 volunteers in the study is advantageous because it allows for a larger sample size, which can increase the statistical power of the results and make it more likely that any observed effects are real rather than due to chance. Additionally, using a larger sample size can help to increase the representativeness of the sample and make the results more generalizable to the population as a whole.

(d) Two variables that were controlled in this experiment were age and health status. Controlling for age is important because memory and cognitive function can decline with age, so it is necessary to ensure that any observed differences between the treatment and placebo groups are not simply due to age-related effects. Controlling for health status is important because underlying health conditions can also affect memory and cognitive function, so it is important to ensure that any observed differences are not due to differences in the health status of the groups.