Answer Happy

rence between the two methods. 2. Regression Analysis for 22 Factorial Experiment A laboratory experiment involves testing of concrete strength at different curing ages of 3 and 28 days. Concrete mixtures were produced at water to cement ratios (W/C) of 0.4 and 0.55. Therefore, two parameters "Age" and "W/C" were used to generate the experimental data for compressive strength. The DOE matrix and compressive strength of two replicate runs for 4 experimental mixtures are reported in the Table below: Experiment Age, days W/C Compressive Strength, psi Run 1 Run 2 0.4 2,555 2,455 0.4 6,325 6,715 0.55 1,815 1,625 D. 28 0.55 4,225 4,755 Answer the following questions: Compute the estimates of the effects and their standard errors for this experiment. Use the t ratio to determine the significance of each effect with a = 0.05. Build and assess the regression model of described experiment using coded variables. For each W/C determine the age in days at which concrete attains the compressive strength of at least 3,000 psi which is considered to be sufficient for structural loading. А 3 B 28 С 3 .