In an experiment to assess the effects of curing time (factor A)

and type of mix (factor B) on the compressive strength of hardened cement cubes, three different curing times were used in combination with four different mixes, with three observations obtained for each of the 12 curing time–mix combinations. The resulting sums of squares were computed to be , and .

a. Construct an ANOVA table.

b. Test at level .05 the null hypothesis H0AB: all (no interaction of factors) against : at least one .

c. Test at level .05 the null hypothesis

(factor A main effects are absent) against HaA: at least one .

d. Test versus HaB: at least one using a level .05 test.

e. The values of the were

, and . Use Tukey’s procedure to investigate significant differences among the three curing times.