/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 39 Construct a \(2^{5}\) design in ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Construct a \(2^{5}\) design in two blocks. Select the \(A B C D E\) interaction to be confounded with blocks.

Short Answer

Expert verified
The design is split into two blocks by confounding them with the interaction \(A B C D E\). Each block has 16 runs.

Step by step solution

01

Understanding the Design

We are tasked with constructing a full factorial design with five factors (A, B, C, D, E), each at two levels. This results in a total of \(2^5 = 32\) experimental runs.
02

Selecting Interaction to Confound

We need to select an interaction to confound with blocks. The interaction specified is \(A \times B \times C \times D \times E\). Confounding reduces experimental runs by splitting them into separate blocks containing errors due to the specified interaction.
03

Assigning Blocks

By selecting the interaction \(A B C D E\) to be confounded, we split the 32 runs into two blocks where the high level of the interaction (\(=1\)) occurs in one block and the low level (\(=0\)) occurs in the other. This ensures our blocks capture the effects of the confounded interaction.
04

Block Formation

Create the two blocks by assigning experimental runs to each block based on the calculated interaction contrast of \(A B C D E\). Runs with an even total of high (\(+1\)) and low (\(-1\)) levels for \(A, B, C, D, E\) are in Block 1 (interaction = 0), while runs with an odd total are in Block 2 (interaction = 1).
05

Verifying Block Construction

Check to ensure each block contains 16 runs, maintaining the balance between blocks resulting from confounding with the interaction. Each block is representative due to equal distribution of high interactions.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Confounding
Confounding occurs when the effects of two or more variables in an experiment cannot be separated. This is not necessarily a bad thing, especially in large factorial designs where it can help simplify the experiment.
In a factorial design, various factors and their interactions can be systematically manipulated. Confounding intentionally mixes a particular interaction with blocks to reduce the number of experimental conditions.
In our exercise, the interaction term \(A \times B \times C \times D \times E\) has been chosen to be confounded with the blocks. This means when analyzing the results, it's not possible to distinguish the block effect from this interaction.
Confounding might seem counterintuitive but it's a strategic choice to balance practical resource limitations with experimental rigor."
Blocking
Blocking is a statistical method used to manage variability, increase precision, and identify error sources in an experiment. Rather than testing all possible conditions, you create blocks of experiments that consider such variations.
Blocking reduces noise resulting from irrelevant factors by isolating the variation attributable to them. In simple terms, it is like grouping similar things together and studying the differences within each group.
In the given exercise, blocking is implemented by dividing the 32 runs into two groups of 16, each capturing different levels of the specified confounding interaction. This ensures systematic control over variability that might obscure the treatment effects we wish to measure."
Interaction Effects
Interaction effects show how multiple factors in a study influence each other. They represent a key part of understanding complex experiments, particularly those with multiple influencing factors.
When two or more factors interact, their combined effect is different from the sum of their individual effects.
This exercise focuses on confounding the five-variable interaction \(A \times B \times C \times D \times E\) with the blocks. This means the focus isn't solely on individual factors, but on how their combined presence or absence affects results. Tracking these interactions helps clarify the true relationship and impact within the design, rather than just individual factor effects."
Experimental Runs
Experimental runs are the different combinations of factor levels in an experiment. They are essentially individual tests or trials within a study, arranged according to the design.
In a factorial \(2^5\) design like in the given exercise, there are expected to be 32 runs for the five factors, each at two levels. These runs map out all possible combinations of factor settings.
Organizing them efficiently, like using blocks, ensures the experiment remains manageable while retaining critical data insights. It's about gaining strong, reliable insights with thoughtful and strategic experimentation, rather than overwhelming with every conceivable trial."

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Most popular questions from this chapter

An article in the Journal of Quality Technology (1985, Vol. \(17,\) pp. \(198-206\) ) described the use of a replicated fractional factorial to investigate the effect of five factors on the free height of leaf springs used in an automotive application. The factors are \(A=\) furnace temperature, \(B=\) heating time, \(C=\) transfer time, \(D=\) hold down time, and \(E=\) quench oil temperature. The data are shown in the following table. (a) What is the generator for this fraction? Write out the alias structure. (b) Analyze the data. What factors influence mean free height? (c) Calculate the range of free height for each run. Is there any indication that any of these factors affect variability in free height? (d) Analyze the residuals from this experiment and comment on your findings. $$ \begin{array}{llllllll} \hline A & B & C & D & E & & \text { Free Height } & \\ \hline- & \- & \- & \- & \- & 7.78 & 7.78 & 7.81 \\ \+ & \- & \- & \+ & \- & 8.15 & 8.18 & 7.88 \\ \- & \+ & \- & \+ & \- & 7.50 & 7.56 & 7.50 \\ \+ & \+ & \- & \- & \- & 7.59 & 7.56 & 7.75 \\ \- & \- & \+ & \+ & \- & 7.54 & 8.00 & 7.88 \\ \+ & \- & \+ & \- & \- & 7.69 & 8.09 & 8.06 \\ \- & \+ & \+ & \- & \- & 7.56 & 7.52 & 7.44 \\ \+ & \+ & \+ & \+ & \- & 7.56 & 7.81 & 7.69 \\ \- & \- & \- & \- & \+ & 7.50 & 7.56 & 7.50 \\ \+ & \- & \- & \+ & \+ & 7.88 & 7.88 & 7.44 \\ \- & \+ & \- & \+ & \+ & 7.50 & 7.56 & 7.50 \\ \+ & \+ & \- & \- & \+ & 7.63 & 7.75 & 7.56 \\ \- & \- & \+ & \+ & \+ & 7.32 & 7.44 & 7.44 \\ \+ & \- & \+ & \- & \+ & 7.56 & 7.69 & 7.62 \\ \- & \+ & \+ & \- & \+ & 7.18 & 7.18 & 7.25 \\ \+ & \+ & \+ & \+ & \+ & 7.81 & 7.50 & 7.59 \end{array} $$

An article in Bioresource Technology ["Medium Optimization for Phenazine-1-carboxylic Acid Production by a gacA qscR Double Mutant of Pseudomonas sp. M18 Using Response Surface Methodology" (Vol. \(101(11), 2010,\) pp. \(4089-4095)]\) described an experiment to optimize culture medium factors to enhance phenazine-1-carboxylic acid (PCA) production. A \(2^{5-1}\) fractional factorial design was conducted with factors soybean meal, glucose, corn steep liquor, ethanol, and \(\mathrm{MgSO}_{4}\). Rows below the horizontal line in the table (coded with zeros) correspond to center points. (a) What is the generator of this design? (b) What is the resolution of this design? (c) Analyze factor effects and comment on important ones. (d) Develop a regression model to predict production in terms of the actual factor levels. (e) Does a residual analysis indicate any problems? $$ \begin{array}{ccccccc} \hline \text { Run } & X_{1} & X_{2} & X_{3} & X_{4} & X_{5} & \text { Production }(\mathrm{g} / \mathrm{L}) \\ \hline 1 & \- & \- & \- & \- & \+ & 1575.5 \\ 2 & \+ & \- & \- & \- & \- & 2201.4 \\ 3 & \- & \+ & \- & \- & \- & 1813.9 \\ 4 & \+ & \+ & \- & \- & \+ & 2164.1 \\ 5 & \- & \- & \+ & \- & \- & 1739.6 \\ 6 & \+ & \- & \+ & \- & \+ & 2483.2 \\ 7 & \- & \+ & \+ & \- & \+ & 2159.1 \\ 8 & \+ & \+ & \+ & \- & \- & 2257.7 \\ 9 & \- & \- & \- & \+ & \- & 1386.3 \\ 10 & \+ & \- & \- & \+ & \+ & 1967.8 \\ 11 & \- & \+ & \- & \+ & \+ & 1306.0 \\ 12 & \+ & \+ & \- & \+ & \- & 2486.9 \\ 13 & \- & \- & \+ & \+ & \+ & 2374.9 \\ 14 & \+ & \- & \+ & \+ & \- & 2932.7 \\ 15 & \- & \+ & \+ & \+ & \- & 2458.9 \\ 16 & \+ & \+ & \+ & \+ & \+ & 3204.9 \\ \hline 17 & 0 & 0 & 0 & 0 & 0 & 2630.4 \\ 18 & 0 & 0 & 0 & 0 & 0 & 2571.6 \\ 19 & 0 & 0 & 0 & 0 & 0 & 2734.5 \\ 20 & 0 & 0 & 0 & 0 & 0 & 2480.4 \\ 21 & 0 & 0 & 0 & 0 & 0 & 2662.5 \end{array} $$ $$ \begin{array}{llccc} \hline \text { Variable } & \text { Component } && {\text { Levels (g/L) }} \\\ \hline & & -1 & 0 & +1 \\ X_{1} & \text { Soybean meal } & 30 & 45 & 60 \\ X_{2} & \text { Ethanol } & 12 & 18 & 24 \\ X_{3} & \text { Corn steep liquor } & 7 & 11 & 14 \\ X_{4} & \text { Glucose } & 10 & 15 & 20 \\ X_{5} & \mathrm{MgSO}_{4} & 0 & 1 & 2 \end{array} $$

An article in the Journal of Coatings Technology (1988, Vol. 60, pp. \(27-32\) ) described a \(2^{4}\) factorial design used for studying a silver automobile basecoat. The response variable is distinctness of image (DOI). The variables used in the experiment are \(A=\) Percentage of polyester by weight of polyester/melamine (low value \(=50 \%,\) high value \(=70 \%)\) \(B=\) Percentage of cellulose acetate butyrate carboxylate (low value \(=15 \%,\) high value \(=30 \%)\) \(C=\) Percentage of aluminum stearate (low value \(=1 \%,\) high value \(=3 \%\) \(D=\) Percentage of acid catalyst (low value \(=0.25 \%,\) high value $$ =0.50 \%) $$ The responses are \((1)=63.8, a=77.6, b=68.8, a b=76.5, c=72.5,\) \(a c=77.2, b c=77.7, a b c=84.5, d=60.6, a d=64.9, b d=72.7, a b d\) \(=73.3, c d=68.0, a c d=76.3, b c d=76.0,\) and \(a b c d=75.9 .\) (a) Estimate the factor effects. (b) From a normal probability plot of the effects, identify a tentative model for the data from this experiment (c) Using the apparently negligible factors as an estimate of error, test for significance of the factors identified in part (b). Use \(a=0.05\). (d) What model would you use to describe the process based on this experiment? Interpret the model. (e) Analyze the residuals from the model in part (d) and comment on your findings.

An experiment to study the effect of machining factors on ceramic strength was described at www.itl.nist.gov/div898/ handbook/. Five factors were considered at two levels each: \(A=\) Table Speed, \(B=\) Down Feed Rate, \(C=\) Wheel Grit, \(D=\) Direction, \(E=\) Batch. The response is the average of the ceramic strength over 15 repetitions. The following data are from a single replicate of a \(2^{5}\) factorial design. \(\begin{array}{rrrrrr}\text { A } & \text { B } & \text { C } & \text { D } & \text { E } & \text { Strength } \\ -1 & -1 & -1 & -1 & -1 & 680.45 \\ 1 & -1 & -1 & -1 & -1 & 722.48 \\ -1 & 1 & -1 & -1 & -1 & 702.14 \\ 1 & 1 & -1 & -1 & -1 & 666.93 \\ -1 & -1 & 1 & -1 & -1 & 703.67 \\ 1 & -1 & 1 & -1 & -1 & 642.14 \\ -1 & 1 & 1 & -1 & -1 & 692.98 \\ 1 & 1 & 1 & -1 & -1 & 669.26 \\\ -1 & -1 & -1 & 1 & -1 & 491.58 \\ 1 & -1 & -1 & 1 & -1 & 475.52 \\ -1 & 1 & -1 & 1 & -1 & 478.76 \\ 1 & 1 & -1 & 1 & -1 & 568.23 \\ -1 & -1 & 1 & 1 & -1 & 444.72\end{array}\) \(\begin{array}{rrrrrr}1 & -1 & 1 & 1 & -1 & 410.37 \\ -1 & 1 & 1 & 1 & -1 & 428.51 \\ 1 & 1 & 1 & 1 & -1 & 491.47 \\ -1 & -1 & -1 & -1 & 1 & 607.34 \\\ 1 & -1 & -1 & -1 & 1 & 620.8 \\ -1 & 1 & -1 & -1 & 1 & 610.55 \\ 1 & 1 & -1 & -1 & 1 & 638.04 \\ -1 & -1 & 1 & -1 & 1 & 585.19 \\ 1 & -1 & 1 & -1 & 1 & 586.17 \\ -1 & 1 & 1 & -1 & 1 & 601.67 \\ 1 & 1 & 1 & -1 & 1 & 608.31 \\ -1 & -1 & -1 & 1 & 1 & 442.9 \\ 1 & -1 & -1 & 1 & 1 & 434.41 \\ -1 & 1 & -1 & 1 & 1 & 417.66 \\ 1 & 1 & -1 & 1 & 1 & 510.84 \\ -1 & -1 & 1 & 1 & 1 & 392.11 \\\ 1 & -1 & 1 & 1 & 1 & 343.22 \\ -1 & 1 & 1 & 1 & 1 & 385.52 \\ 1 & 1 & 1 & 1 & 1 & 446.73\end{array}\) (a) Estimate the factor effects and use a normal probability plot of the effects. Identify which effects appear to be large. (b) Fit an appropriate model using the factors identified in part (a). (c) Prepare a normal probability plot of the residuals. Also, plot the residuals versus the predicted ceramic strength. Comment on the adequacy of these plots. (d) Identify and interpret any significant interactions. (e) What are your recommendations regarding process operating conditions?

Four factors are thought to influence the taste of a soft-drink beverage: type of sweetener \((A),\) ratio of syrup to water \((B),\) carbonation level \((C),\) and temperature \((D) .\) Each factor can be run at two levels, producing a \(2^{4}\) design. At each run in the design, samples of the beverage are given to a test panel consisting of 20 people. Each tester assigns the beverage a point score from 1 to \(10 .\) Total score is the response variable, and the objective is to find a formulation that maximizes total score. Two replicates of this design are run, and the results are shown in the table. Analyze the data and draw conclusions. Use \(a=0.05\) in the statistical tests. $$ \begin{array}{ccc} \hline \ {\begin{array}{c} \text { Treatment } \\ \text { Combination } \end{array}} & {\text { Replicate }} \\ \ & \text { I } & \text { II } \\ \hline(1) & 159 & 163 \\ a & 168 & 175 \\ b & 158 & 163 \\ a b & 166 & 168 \\ c & 175 & 178 \\ a c & 179 & 183 \\ b c & 173 & 168 \\ a b c & 179 & 182 \\ d & 164 & 159 \\ a d & 187 & 189 \\ b d & 163 & 159 \\ a b d & 185 & 191 \\ c d & 168 & 174 \\ a c d & 197 & 199 \\ b c d & 170 & 174 \\ a b c d & 194 & 198 \end{array} $$

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