When looking at the percentage of patients whose symptoms were relieved after taking a placebo, a scientist sees a 20% success rate. the success rate of patients whose symptoms were relieved after taking a new composite drug was 30%. the scientist determines that the margin of error is 10%, which indicates that the new drug had no statistically significant positive effect. in which stage of the engineering process is this scientist?

a. evaluating test results
b. screening
c. identifying a need
d. looking for future improvements