Achemical reactionwas run using two levels each of temperature (A), reagent concentration (B), and pH (C). For each factor, the high level is denoted 1, and the low level is denoted ˆ’1. The reaction was run twice for each combination of levels, and the yield (in percent) was recorded. The results were as follows.

a. Compute estimates of the main effects and interactions, and the sum of squares and P-value for each.
b. Which main effects and interactions, if any, are important?
c. Other things being equal, will the mean yield be higher when the temperature is high or low? Explain.

C Yields Mean Yield -1 74, 71 173, 74 72.5 73.5 76.0 87.5 69.5 77.0 80.0 87.0 -1 I78, 74 86, 89 1 71, 68 1-1 1 75, 85 1 92, 82