A chemical engineer is investigating in certain processes, the effect of operating temperature (T) and the yield (R) of the product. In the study, a sample is taken, obtaining the following:

 

a) To increase performance, improvements have been incorporated so that the performance of the product increases by 10%. After the improvements obtain: average performance, variance and coefficient of variability. With the improvements, does the product's performance become more homogeneous? Justify.

b) What is the minimum operating temperature that represents the 30% of the processes with the highest operating temperature? 

Temperatura (C) Rendimiento (%) 40-50 50-60 60-70 70-80 100-120 3 2 1 0 120-140 2 4 2 1 140-160 1 3 7 5 160-200 0 1 3. 2