Homework2_S11

# Homework2_S11 - STAT 496 Spring 2011 Homework Assignment#2...

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STAT 496, Spring 2011 Homework Assignment #2, Due by Thursday, February 3 1. The three fundamental principles of a designed experiment are: control of outside variables, randomization, and replication. Consider each of the following scenarios. Does each adhere to all three principles? If so, describe how. If not, indicate how you would change the design to incorporate the missing principle(s). If a principle is partially adhered to but could be improved, comment on what you would do to improve the experiment. Be specific and be sure to comment on all three principles. a) An experiment is performed to evaluate the effect of drill speed on the size of drilled holes. A single 0.25 inch drill bit in a vertical head milling machine is used for the experiment. All drilling is done by the same operator. A single bar steel with a Brinell hardness of 400 is used. Four speeds are evaluated: 200, 250, 300 and 350 rpms. The operator picks a speed at random from the four and will drill 20 holes. The process is repeated, picking a speed at random from those remaining and drilling 20 holes until all 4 speeds have been used. After all of the holes are drilled, each of the holes is measured using a special caliper. The order in which the 80 holes are measured is done

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## This note was uploaded on 02/11/2012 for the course STAT 496 taught by Professor Staff during the Spring '08 term at Iowa State.

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Homework2_S11 - STAT 496 Spring 2011 Homework Assignment#2...

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