weight update.

This figure shows Abram's weight in pounds as a function of time in days after birth. He is currently 59 days old. The solid data points mark measurements at birth, at our discharge from the hospital, and at our first, second, and third appointments with the pediatrician. The solid blue curve is a natural cubic spline fit to the data with an extrapolation. The dashed red curve is a linear fit to the last two data points. The green square marks the expectation that he will gain roughly 1 ounce per day. Which of these is the best estimate for Abram's weight in another 35 days? The open blue squares mark his most recent weight measurements. As you can see, the linear extrapolation from the last two solid data points is doing an excellent job. However, it predicts Abram's weight will reach nearly 40 pounds by next May!