A contract engineer at DuPont Corp. studied the rate at which a spilled volatile liquid will spread across a surface (Chemical Engineering Progress, Jan. 2005). Assume 50 gallons of methanol spills onto a level surface outdoors. The engineer used derived empirical formulas (assuming a state of turbulent-free convection) to calculate the mass (in pounds) of the spill after a period of time ranging from 0 to 60 minutes. The calculated mass values are given in the accompanying table.

a. Construct a scattergram for the data, with y = calculated mass and x = time.

b. Find the least-squares line relating mass (y) to time (x).

c. Plot the least-squares line on the graph, part a.

d. Interpret the values of β̂_o and β̂₁.

LIQUIDSPILL Time Mass Time Mass (minutes) (pounds) (minutes) (pounds) 6.64 22 1.86 1 6.34 24 1.60 2 6.04 26 1.37 5.47 28 1.17 4.94 30 0.98 8 4.44 35 0.60 10 3.98 40 0.34 12 3.55 45 0.17 14 3.15 50 0.06 16 2.79 55 0.02 18 2.45 60 0.00 20 2.14