Question

An experiment is being designed to compare relief from hay fever symptoms given by a low dose of a drug, a high dose of the drug, and a placebo. Each subject who suffers from hay fever and volunteers for the study is observed on three separate days, with a different treatment used each day. There are two days between treatments, so that a treatment does not have a carry-over effect for the next treatment assigned.

If the experiment is properly randomized and the study reveals a statistical difference between treatments, which of the following is true?
i. The study can conclude that the treatment is the cause of the difference in hay fever symptoms.
ii. The results of the study can be generalized to the population of all hay fever sufferers
a) Statement ii is correct.
b) Neither of the two statements are true.
c) Statement i is correct.

Answer 1

c) Statement i) is correct

Explanation:

Experiment designed to compare relief from hay fever symptoms, by a low or high dose of a drug or placebo, with different hay fever patient volunteers given 3 different treatments (with sufficient gap) :

If the properly randomised experiment design reveals statistical difference between treatments - It states that study concludes, treatments have significantly different impacts on hay fever symptoms, & so treatment is the cause of the difference in hay fever symptoms. (i)

However, it doesn't necessarily state that these study results can be generalized to the population of all hay fever sufferers. (ii)