Question

Dr. Richard Hurt and his colleagues ( Hurt et al., 1994) randomly assigned volunteers wanting to quit smoking to wear either a nicotine patch or a placebo patch to determine whether wearing a nicotine patch improves the chance of quitting. After 8 weeks of use, 46% of those wearing the nicotine patch but only 20% of those wearing the placebo patch had quit smoking.

Was this a randomized experiment or an observational study?

The difference in the percentage of participants who quit (20% versus 46%) was statistically significant. What conclusion can be made on the basis of this study?

Why was it advisable to assign some of the participants to wear a placebo patch?

Answer 1

This is a randomized experiment. The difference in the percentage of participants who quit (20% versus 46% was statisticaly significant. Here we can conclude that the population proportion of those wearing the nicotine significantly differ from the population proportion of those wearing placebo patch We know that in experiment the purpose of the placebo group is to account for the placebo effect, that is, effects from treatment that do not depend on the treatment itself. Here placebo patch added to get the placebo effect in the experiment. We know that the placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. To get the real effect of the study it advisable to assign some of the participants to wear a placebo patch.