What are the three primary technical tools used for quality control and improvement?

$1\mathrm{.}15.$ What is a six$-$sigma process?

$1\mathrm{.}21.$ Explain why it is necessary to consider variability around the mean or nominal dimension as a measure of quality.

$1\mathrm{.}25.$ Suppose you had the opportunity to improve quality in a hospital. Which areas of the hospital would you look to as opportunities for quality improve$-$ment? What metrics would you use as measures of quality?

$2\mathrm{.}8.$ Why are designed experiments most useful in the improve step of DMAIC?

$2\mathrm{.}18.$ Suppose that you want to improve the process of loading passengers onto an airplane. Would a discrete$-$event simulation model of this process be useful?

What data would have to be collected to build this model?