Researchers G. Evans and E. Kantrowitz explored the health consequences for exposure to many different environmental risks in the journal article “Socioeconomic Status and Health: The Potential Role of Environmental Risk Exposure” (Annual Review of Public Health, Vol. 23, No. 1, pp. 303–331). According to research, 65% of preschool children living in poverty have been exposed to cigarette smoke at home. In comparison, 45% of preschool children not in poverty have been exposed to cigarette smoke at home.

a. If 200 preschool children living in poverty are selected at random, what is the probability that at least 125 have been exposed to cigarette smoke at home?
b. Repeat part (a) for children not living in poverty.