Chapter 9 Lab : Confidence Intervals for Proportions

Confidence Interval - Is an interval of values computed from sample data that is likely to include the true population value. If we consider all possible randomly selected samples of the same size from a population, the confidence level is the fraction or percent of those samples for which the confidence interval includes the population parameter. Common confidence levels are 80%, 90%, 95%, and 99%.

On March 4, 1999, New England Journal of Medicine published a research article by Dr. Douglas Jorenby and colleagues comparing the different methods used to stop smoking.

Calculate P hat for each treatment and record fraction in last column of the table.

Treatment

Subject Participating

Subjects not Smoking after 6 months

P hat (