Question

The table gives the average weights in kg of girls from birth to age 10

(a) Make a scatter plot of the data, draw a line of best fit, and then find the equation of the line of best fit. Show and explain your work.
(b) Describe what the slope of the line of best fit represents.
(c) Use the equation to predict the average weight in kg of 14-year-old girls. Show your work.

Answer 1

(a) Make a scatter plot of the data using online calculator. The graph contains all points from the table (green points).

As you can see these points lie nearly on the same line. The equation of this line is y=2.5x+5.5 and the graph is shown as black line. Here variable x represents age and variable y represents weight.

(b) The slope of this line is m=2.5. It shows the average rate of change of the linear function or simply the growth in weight after one year spent.

(c) When you have to predict the average weight in kg of 14-year-old girls, then x=14 and

y=2.5·14+5.5=35+5.5=40.5 kg