Lisa goes to school by bicycle 60% of the time and by bus 40% of the time. If she uses her bicycle she arrives on time 95% of the time but if she catches the bus she comes late 2% of the time.
1. Draw fully labelled tree diagram and then find the probability that Lisa arrives on time on any particular day.
2. In any day by using bicycle, Lisa passes through three traffic lights on her way to school, and each light is equally likely to be green or red, independent of the others. What is the PMF, the mean, and the variance of the number of red lights that Lisa encounters?
1. Draw fully labelled tree diagram and then find the probability that Lisa arrives on time on any particular day.
2. In any day by using bicycle, Lisa passes through three traffic lights on her way to school, and each light is equally likely to be green or red, independent of the others. What is the PMF, the mean, and the variance of the number of red lights that Lisa encounters?
