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Experimental design STAT 430 / 830
Assignment #3
Purpose of this assignment: let you explore the material of chapters 11 (3-level experiments), 12
(optimizing response surface models) and 13 (random-effects models), and thus help you to prepare for the
final exam.
– Deadline for submitting your solutions: . Solutions submitted after this
deadline will be graded as 0.
– How to submit? You will get an invitation to submit your solutions on Crowdmark.
– Rules of the game: It is allowed to work on this assignment together with a fellow student, but you must
write up your solutions individually and each must submit their own solutions.
– The assignment will be discussed in the tutorial
1. Determining the precision of collar-size measurements
In class, we discussed gage R&R studies, and we conducted such experiment to determine the precision of
collar-size measurements. Analyze the data from the class-room experiment. Use this procedure in Minitab:
Stat > Quality Tools > Gage Study > Gage R&R Study (Crossed). The data are on LEARN (dataset.xlsx)
a) What is the precision of the collar-size measurements? Give the width of a 99% confidence interval
on the true collar size.
b) What is Var�
