A new medication has been developed to treat sleep onset insomnia. Researchers want to compare this drug to a drug that has been used in the past by comparing the length of time it takes subjects to fall asleep. Of the following, which is the best method for obtaining this information.
a)Randomly assign the subjects to two groups, giving the new drug to one group and the old drug to the other group, then compare the results.
b)An Experiment can show a direct cause-and-effect relationship, whereas an observational study cannot.
c)The new drug may affect hypertensive and non hypertensive people differently.
d)All of these