Question

The equation y = 6.3x + 67.4 is the equation of a linear model in a scatter plot comparing the ages of boys between 2 and 10 years old open (x) and their average heights in centimeters open (y).
What is the average height of a 5-year-old boy?


98.9 cm


78.7 cm


67.4 cm


62.4 cm

Answer 1

Since the age of the boy is represented using x,
when the boy is 5 years old, x = 5.
y = 6.3x + 67.4
= 6.3(5) + 67.4
= 98.9

Since the average height of an age group is represented using y,
when y = 98.9, the average height of a 5-year-old boy is 98.9 cm.

The answer is 98.9 cm.