Suppose that the growth rate of children looks like a straight line if the height of a child is observed at the ages of 24 mont
hs, 28 months, 32 months, and 36 months. If you use the regression obtained from these ages and predict the height of the child at 21 years, you might find that the predicted height is 20 feet. What is wrong with the prediction and the process used?
The growth rate of a child is not constant, so height versus time does not look like a straight line. Nothing is wrong with the prediction made using the false assumption. You can conclude anything you like when you start with a false premise.
The two straight lines around the number indicate absolute value. Absolute value is the distance from the number to zero (essentially how many marks away on a number line).
