A pediatrician wants to determine the relation that may exist between a child's height and head circumference.

Question:

A pediatrician wants to determine the relation that may exist between a child's height and head circumference. She randomly selects eleven 3-yearold children from her practice, measures their heights and head circumference, and obtains the data shown in the table below.

Height Height (inches) Circumference (inches) Circumference Head Head (inches) (inches) 27.75 17.5 26.5 17.3 24.5 17.1 2

(a) If the pediatrician wants to use height to predict head circumference, determine which variable is the explanatory variable and which is the response variable.
(b) Draw a scatter diagram of the data.
(c) Compute the linear correlation coefficient between the height and head circumference of a child.
(d) Does a linear relation exist between height and head circumference?
(e) Convert the data to centimeters 11 inch = 2.54 cm2, and recompute the linear correlation coefficient. What effect did the conversion have on the linear correlation coefficient?