The following data were obtained from a study- on a

Question

The following data were obtained from a study- on a chemical reaction system:

The 16 runs were perfom1ed in random order, trial 1 being run three times, trial 5 once, and all the rest twice. (The intention was to nm each test twice, but a mistake was made in setting the concentration level on one of the tests.)

(a) Analyze these data. One thing you might wish to consider is fitting by weighted least squares the following model to them: η = β₀ + β₁x₁ + β₂x₂ + β₃x₃ where x₁, x₁, and x₃ (preferably, though not necessarily, in coded units) refer to the variables temperature, concentration, and pH, respectively, and 71 is the mean value of the yield. Alternatively, a good indication of how elaborate a model is needed will be obtained by averaging the available data and making a preliminary factorial analysis on the resuIts.

(b) Compare these two approaches.