Construction of Scatter Diagram, Lines of Best Fit and Interpretation of Data

Construction of a scatter diagram consists of:

1. Plotting the data points on a coordinate plane.
2. Representing each data point by a mark (e.g., dot, circle, or square).

We solve an example to understand the concept.

Example:

Table below shows the masses and heights of 11 boys.

a) Draw a scatter diagram for the above data.

b) What type of correlation is observed in the scatter diagram?

c) Draw a line of best fit on the scatter diagram.

d) Use this line of best fit to estimate mass of a boy whose height is $150\mathrm{c}\mathrm{m}$$150\mathrm{cm}$.

Solution (a):

(b) From the graph, it is observed that there is a strong positive correlation between masses and heights of boys. More height, more the mass of boys.

(c) Line of best fit is drawn having almost half the data points on either sides of it.

(d) From scatter diagram, the boy with height $150\mathrm{c}\mathrm{m}$$150\mathrm{cm}$ should have a mass of $39\mathrm{k}\mathrm{g}$$39\mathrm{kg}$ app.