Chapter 4, Problem 7CR

In Problems 9-14,

(a) Draw a scatter diagram for the data.

(b) Find $\bar{x},\bar{y},b$, and the equations of the least-squares line. Plot the line on the scatter diagram of part (a).

(c) Find the sample correlation coefficient r and the coefficient of determination $r^2$. What percentage of variation in y is explained by the least-squares model?

Medical: Fat Babies Modem medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x of a 1-year-old baby and the weight y of the mature adult (30 years old)? A random sample of medical files produced the following information for 14 females:

x(lb)	21	25	23	24	20	15	25	21	17	24	26	22	18	19
y (lb)	125	125	120	125	130	120	145	130	130	130	130	140	110	115

Complete parts (a) through (c). given

${\displaystyle \sum }x=300;{\displaystyle \sum y}=1775:{\displaystyle \sum x^2}=6572;{\displaystyle \sum y^2}=226.125:{\displaystyle \sum xy}=\mathrm{38.220.}$

(d) If a female baby weighs 20 pounds at 1 year, what do you predict she will weigh at 30 years of age?