The solubility of a solution was examined for six different temperature settings, shown in the accompanying table.
y, Solubility by Weight x, Temperature (° C)
43, 45, 42.......................................... 0
32, 33, 37......................................... 25
21, 28, 29......................................... 50
15, 14, 9.......................................... 75
12, 10, 8......................................... 100
7, 6, 2............................................ 125
a. Plot the data, and fit as appropriate.
b. Test for lack of fit if possible. Use α = .05.
c. Examine the residuals and draw conclusions.