Tham khảo tài liệu 'engineering statistics handbook episode 7 part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Fractional factorial example ENGINEERING STATISTICS HANDBOOK HOME TOOLS Ậ AIDS SEARCH BACK Niltfl 5. Process Improvement . Analysis of DOE data . Examples of DOE s . Fractional factorial example A Catapult Fractional Factorial Experiment A step-by-step analysis of a fractional factorial catapult experiment The experiment has five factors that might affect the distance the golf ball travels This experiment was conducted by a team of students on a catapult - a table-top wooden device used to teach design of experiments and statistical process control. The catapult has several controllable factors and a response easily measured in a classroom setting. It has been used for over 10 years in hundreds of classes. Below is a small picture of a catapult that can be opened to view a larger version. Catapult Description of Experiment Response and Factors Purpose To determine the significant factors that affect the distance the ball is thrown by the catapult and to determine the settings required to reach 3 different distances 30 60 and 90 inches . Response Variable The distance in inches from the front of the catapult to the spot where the ball lands. The ball is a plastic golf ball. Number of observations 20 a 25-1 resolution V design with 4 center points . Variables 1. Response Variable Y distance 2. Factor 1 band height height of the pivot point for the rubber bands - levels were and inches with a centerpoint level of 3. Factor 2 start angle location of the arm when the operator releases- starts the forward motion of the arm - levels were 0 and 20 degrees with a centerpoint level of 10 degrees 4. Factor 3 rubber bands number of rubber bands used on the catapult- levels were 1 and 2 bands 5. Factor 4 arm length distance the arm is extended - levels were 0 and 4 inches with a centerpoint level of 2 inches 6. Factor 5 stop angle location of the arm where the forward motion of the arm is stopped and the ball starts flying - levels were 45
