Question

A randomized controlled, double-blind trial was conducted to see whether sustained-release bupropion drug provided benefit over use of the nicotine patch alone in helping people stop smoking. The control group (nicotine patch alone) included 244 smokers who wanted to stop smoking. The treatment group consisting of 245 individuals who received sustained-release bupropion drug in combination with a nicotine patch. After one year, 40 individuals in the control group remained smoke free. In contrast, 87 people in the group reported being smoke free (Jorenby et al., 1999). Hint: Two sample proportions. a) Calculate the incidence proportions of the cessation groups b) Test the difference in proportions for significance and use alpha = 0.05.

You must show all your work for full points. Carry probabilities to at least four decimal places for intermediate steps. For extremely small probabilities, it is important to have one or two significant non-zero digits, for example, 0.000001 or 0.000034. Round off your final answer to two decimal places.

Answer 1

Let

p₁= proportion of individuals in control group remained smoke free

p₂= proportion of individuals in the treatment group reported being smoke free

a)

b)

The test statistics is given by

hence, assuming H₀ is true, the test statistics is

The p-value is

As p-value is less than alpha=0.05, we have sufficient evidence to reject H₀.

We have sufficient evidence to conclude that sustained-release bupropion drug provided benefit over use of the nicotine patch alone in helping people stop smoking.