Question

Tiana compares the length of a name on a nameplate to the number of letters in the name. She draws the scatterplot below, and then she plots and determines an equation for the trend line.

Nameplates
A graph has letters on the x-axis and length (inches) on the y-axis. A trend line goes through points (2, 5) and (4, 8). The regression equation is y = 1.47 x + 2.05.


Based on the information above, which is the best estimate of the number of letters that a name contains if the nameplate is 6 inches long?
3
4
10
12

Answer 1

Use the regression equation y = 1.47x + 2.05 with y = 6.
x = (6 − 2.05)/1.47 ≈ 3.95/1.47 ≈ 2.69, so about 3 letters. Answer: 3.