Question

The next three questions relate to the following situation:

A randomised experiment was conducted by randomly assigning each participant to either walk for half an hour three times a week or to sit quietly and read a book for half an hour three times a week. At the end of a year the change in participant's blood pressure was measured, and the change was compared for the two groups.

The two treatments for the study were:

Answers: A. Walking for half an hour three times a week and reading a book for half an hour three times a week B. Walking or reading a book for half an hour three times a week and doing nothing. C. Having blood pressure measured at the beginning of the study and having blood pressure measured at the end of the study D. Walking or reading a book for half an hour three times a week and having blood pressure measured If a statistically important difference in blood pressure change at the end of the year for the two activities was found then: Answers: A. It cannot be claimed that the difference in activity caused a difference in the change in blood pressure because in the course of a year there are lots of possible confounding variables. B. It can be claimed that there is evidence to suggest that the difference in activity caused a difference in the change in blood pressure. C. It cannot be claimed that the difference in activity caused a difference in the change in blood pressure because it might be the opposite, that people with high blood pressure were more likely to read a book than to walk. D. Whether or not the difference was caused by the difference in activity depends on what else the participants did during the study.

please answer these two quetions

Answer 1

1) A

Explanation: In the above study, the effect of either walking for half an hour three times a week or to sit quietly and read a book for half an hour three times a week on the participants blood pressure is being measured.

Here, Independent variable is walking and reading.

Dependent/ Response variable is blood pressure.

Treatments are the independent variables ie; the objects used for comparison. Hence option A is correct.

2) B

Explanation: Option B is relevant as information on other factors responsible for changes in blood pressure is not provided. Also, if statistically important difference in blood pressure change at the end of the year for the two activities was found implies that the Null hypothesis is being rejected which leads to acceptance of alternative hypothesis and hence provides evidence that the difference in activity caused the difference in the change in the blood pressure.