Develop life tables for subsets of the data based on age, gender, number of cigarettes per day, and CO level (one variable at a time). Given these data, do you feel age, gender, number of cigarettes per day, and/or CO level are related to success in quitting? (Methods of analysis for lifetable data are discussed in more detail in Chapter 14.) 

Health Promotion
A study was conducted among 234 people who had expressed a desire to stop smoking but who had not yet stopped. On the day they quit smoking, their carbonmonoxide level (CO) was measured and the time was noted from the time they smoked their last cigarette to the time of the CO measurement. The CO level provides an “objective” indicator of the number of cigarettes smoked per day during the time immediately before the quit attempt. However, it is known to also be influenced by the time since the last cigarette was smoked. Thus, this time is provided as well as a “corrected CO level,” which is adjusted for the time since the last cigarette was smoked. Information is also provided on the age and sex of the participants as well as each participant’s self-report of the number of cigarettes smoked per day. The participants were followed for 1 year for the purpose of determining the number of days they remained abstinent. Number of days abstinent ranged from 0 for those who quit for less than 1 day to 365 for those who were abstinent for the full year. Assume all people were followed for the entire year.