A family has two children. Find the probability that both children are girls, given that at least one of the two is a girl who was born in winter. Please assume that (i) gender is binary, i. e., a boy or a girl, (ii) P (a boy) = P (a girl) = 1/2, (iii) genders of the two children are independent, i. e., knowing one’s gender gives no information about the other’s gender, (iv) four seasons are equally likely, and (v) gender is independent of season.

Data from 2005 for various age groups show that for each $100 increase in the median weekly income for whites, the median weekly income of blacks increases by $105. also, for workers of ages 25 to 54 the median weekly income for whites was $676 and for blacks was $527. (a) let w represent the median weekly income for whites and b the median weekly income for blacks, and write the equation of the line that gives b as a linear function of w. b = (b) when the median weekly income for whites is $760, what does the equation in (a) predict for the median weekly income for blacks?