The following data represent a single replicate of a 25 design that is used in an experiment to study the compressive strength of concrete. The factors are mix (A), time (B), laboratory (C), temperature (D), and drying time (E).

(a) Estimate the factor effects.

(b) Which effects appear important? Use a normal probability plot.

(c) If it is desirable to maximize the strength, in which direction would you adjust the process variables?

(d) Analyze the residuals from this experiment.

= 700 = 900 = 3400 (1) 800 = 1200 ae abe = 6200 ab = 5500 = 600 = 1000 ce ac 1200 ace