4.) In a hypothetical study about the relationship between the income of parents (x) and the IQs of their children (y), the equation of the least-squares regression line was calculated and determined to be:

= 86.5 + 0.0003x

a.) If a parent's income is $80,000 what would you predict the child's IQ to be?

b.) What income would you predict to be necessary in order for the child to have an IQ of 120?

c.) If income is increased by $10,000 how much would you predict a child's IQ to differ?