The bus route of west campus goes through a path that includes seven lights. the probability of hitting zero lights is 0.05; the probability of hitting only one light is 0.10; the probability of hitting two lights is 0.10; the probability of hitting three lights is 0.15; the probability of hitting four lights is 0.20; the probability of hitting five lights is 0.15; the probability of hitting six lights is 0.20; the probability of hitting seven lights is 0.05. the mean and standard deviation of the number of lights can be calculated using the model.