Women also were asked how difficult they
would find it to quit smoking and responded on a
four-point scale (very or somewhat difficult,
somewhat or very easy). Nicotine addiction was
assessed by using the four items Fagerstrom nicotine
addiction scale (Fagerstrom and Schneider,
1989; Heatherton et al.,1991). Missing values on
any variable led to exclusion of that observation.
Only 15 observations were excluded.