# Shared Flashcard Set

## Details

ISE 610- Design of Experiments
Quiz 1
27
Engineering
10/17/2011

Term
 What causes randomness?
Definition
 the variation of factors we are not controlling, or possibly even considering
Term
 What are blocking factors?
Definition
 Controllable inputs that are not of primary interest
Term
 What is a noise factor?
Definition
 inputs that are controllable during experimentation, but not during normal system operations
Term
 If one fails to find significance in hypothesis testing, it might still be possible to find significance if? (2 answers)
Definition
 1) Additional test runs performed2) Different levels analyzed3) Different factors held constant
Term
 Given 1 factor with 2 levels, what type of test would you perform to determine if there is significance? What is the basic procedure of this type of test?
Definition
 T-test.1) Find avg. of y1 and y22) Find s1 and s2 w/ formula3) Find s(p) given s1 and s24) Find t(o) from formula and look up t(crit) in a table5) if t(o)>t(crit), there is significance at given alpha level
Term
 How, in general, do you perform a double blind experiment and account for blocking factors?
Definition
 There is a master experimenter who knows which levels are receiving "placebo" vs. the real thing. The thing being tested is coded in a way that only the master experimenter knows, and gives the people running the exp. numbers only so they do not know who is getting what. Blocking factors are accounted for by having the experimenter not know the gender or the nationality of the test subject.
Term
 Where do critical values come from and how can they be derived?
Definition
 Crit. values derive from the assumption that all responses come from same distribution, and no effects assoc. w/ level changes being studied.By repeating approx. 10,000 simulated experiments, we can find a typical large value that might happen by chance near the value we look up in a table.
Term
 Can we perform randomized experiments on a planetary scale? Why or why not?
Definition
 No, the scale is simply too large, therefore we would have to rely on planetary models and simulations.
Term
 Is randomization necessary to conclude direct empirical proof?
Definition
 Yes, without randomization, no direct empirical proof is possible- evidence is possible however
Term
 What does Tukey's Method do?
Definition
 Tukey's Method is a multiple comparison procedure similar to ANOVA + LSD combo. Based on a single step and designed to limit type 1 error.
Term
 Given 1 factor and more than 2 levels, what test is appropriate and what is basic procedure?
Definition
 F-test.1) Organize data into matrix- each column = a level2) set data matrix = grand mean matrix + estimated effects matrix + residuals matrix3) Calc. SS, df's, and MS for factors and residuals4) Calculate F(o) and look up F(crit)5) If F(o) > F(crit), we can conclude significance between the levels, but don't know which ones.
Term
 When ANOVA finds significance, how do we determine which levels are significantly better than other levels? Briefly describe the procedure.
Definition
 LSD Test.1) Calculate the absolute value of all y-bar difference combos.2) Calculate LSD using formula.3) Compare each absolute value calculated previously to this LSD value.4) If a difference is greater than the LSD, than we can conclude significance between those two y-bar levels.
Term
 Why do t-tests sometimes show significance between 2 level comparisons, when an ANOVA does not?
Definition
 A type 1 error is highly likely when using t-tests on multiple level comparisons. ANOVA should be used in this case to avoid these falsified significance declarations.
Term
 Why is run order important?
Definition
 If the run order is not randomized, then we cannot generate empirical proof. The chance of systematic bias or error is likely without randomization.
Term
 Define sample mean.
Definition
 An average of measured values.
Term
 How do you calculate the "estimated effect" in an ANOVA test?
Definition
 The column average minus the grand mean (for balanced orthogonal designs). Difference between the model prediction conditioned on a level and the grand mean.
Term
 What is randomization?
Definition
 The allocation of blocking factor levels including run order in an un-patterned way
Term
 What is a residual/ how is it calculated?
Definition
 The difference between the model prediction (column avg.) and the actual values. Aka "estimated error."
Term
 What is a fractional factorial experiment?
Definition
 A subset of a full factorial experiment. A randomized plan involving fewer than all combinations of relevant factor levels.
Term
 What is a level?
Definition
 A setting that a factor can assume.
Term
 What is a 'main effect?'
Definition
 the difference in the avg. response when a factor is at the high level minus the avg. at the low level.
Term
 Define 'non-parametric.'
Definition
 not associated with any specific distributional assumption
Term
 What is a random variable?
Definition
 a number with an unknown value at the time of planning by the planner.
Term
 What is the purpose of a master guide sheet?
Definition
 To aid in experimental planning.
Term
 What is an empirical model?
Definition
 A quantitative input-output relationship derived from experimental data
Term
 What is a p-value?
Definition
 A value of alpha that makes the test statistic equal to the critical value
Term
 Why would Tukey's method be preferred over other approaches?
Definition
 Has a lower chance of making at least 1 type 1 error. (but higher type 2 rate)
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