1 .suppose that family incomes in a town or normally distributed with a meeting of $1,120 and a standard Deviation of $ 600 per month. What is the probability that a given family has an income over $ 2000 per month ?
2 . During the last week of the semester , students at a certain college spends on the average 4.2 hours using the school's computer terminals with a standard deviation of 1.8 hours for a random sampling of 36 students at that collage , find the average time spent using the compute terminal during the last week of the semester
a, at least 4.8 hours
b, between 4.1 and 4.5 hours