49. 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—mixcombinations. The resulting sums of squares were computed to be SSA30,763.0, SSB34,185.6, SSE97,436.8, and SST  205,966.6.

a. Construct an ANOVA table.

b. Test at level .05 the null hypothesis H0AB: all gij s  0 (no interaction of factors) against H0AB:

at least one gij  0.

c. Test at level .05 the null hypothesis H0A: a1 

a2  a3 0 (factor A main effects are absent)

against HaA: at least one ai  0.

d. Test H0B: b1  b2  b3  b4  0 versus HaB: at least one bj  0 using a level .05 test.

e. The values of the s were

. UseTukey s procedure to investigate signi cant differences among the three curing times.