Problem: Researchers at WCU wanted to examine unsafe driving behavior (UDB) among their students. One independent variable of interest was cigarette smoking. A survey was conducted. Among 160 smokers, 80 had engaged in an unsafe driving behavior in the past month. Among 100 non-smokers, 50 had engaged in an unsafe driving behavior in the past month.
What is the prevalence of not engaging in unsafe driving behavior in the past month?