Exam 11: Multifactor Analysis of Variance

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Which of the following statements are not true?

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In the fixed effects model with interaction, assume that there are 3 levels of factor A, 2 levels of factor B, and 3 observations for each of the six combinations of levels of the two factors. Then the critical value for testing the null hypothesis of no interaction between the levels of the two factors at the .05 significance level is

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In a two-factor experiment where factor A consists of I levels, factor B consists of J levels, and there is only one observation on each of the IJ treatments, SSE has __________ degrees of freedom.

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Which of the following statements are true?

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Which of the following statements are true?

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Assume the existence of I parameters α1,α2,,αi\alpha _ { 1 } , \alpha _ { 2 } , \ldots \ldots , \alpha _ { i } and J parameters β1,β2,,βi\beta _ { 1 } , \beta _ { 2 } , \ldots \ldots , \beta _ { i } such that Xy=α2+βj+εy(i=1,,I and j=1,,J) and μy=α2+βjX _ { y } = \alpha _ { 2 } + \beta _ { j } + \varepsilon _ { y } ( i = 1 , \ldots \ldots , I \text { and } j = 1 , \ldots \ldots , J ) \text { and } \mu _ { y } = \alpha _ { 2 } + \beta _ { j } \text {. } The model specified by the above equations is called an __________ model because each mean response μy\mu _ { y} is the __________ of an effect due to factor A at level i(α1)i \left( \alpha _ { 1 } \right) and an effect due to factor B at level j(βj)j \left( \beta _ { j } \right) .

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Which of the following statements are not true?

(Multiple Choice)
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In the three-factor fixed effects model, assume that there are 4 levels of factor A, 2 levels of factor B, 4 levels of factor C, and 3 observations for each combination of levels of the three factors. Then, the number of degrees of freedom for the three-factor interaction sum of squares (SSABC) is

(Multiple Choice)
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In the fixed effects model with interaction, assume that there are I levels of factor A, J levels of factor B, and K observations (replications) for each of the IJ combinations of levels of the two factors. Then SST (the total sum of squares) has df = __________.

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The accompanying data was obtained in an experiment to investigate whether compressive strength of concrete cylinders depends of the type of capping material used or variability in different batches. Each number is a cell total

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Which of the following statements are not true?

(Multiple Choice)
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The following equation SST = SSA + SSB +SSC + SSAB + SSAC + SSBC + SSABC + SSE applies to which ANOVA model?

(Multiple Choice)
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A data from an experiment to assess the effects of vibration (A), temperature cycling (B), altitude cycling (C), and temperature for altitude cycling and firing (D) on thrust duration are shown below. Use the Yates method to obtain sums of squares and the ANOVA table. Then assume that three- and four-factor interactions are absent, pool the corresponding sums of squares to obtain an estimate of σ2\sigma ^ { 2 } and test all appropriated hypotheses at level .05.  A data from an experiment to assess the effects of vibration (A), temperature cycling (B), altitude cycling (C), and temperature for altitude cycling and firing (D) on thrust duration are shown below. Use the Yates method to obtain sums of squares and the ANOVA table. Then assume that three- and four-factor interactions are absent, pool the corresponding sums of squares to obtain an estimate of  \sigma ^ { 2 }  and test all appropriated hypotheses at level .05.

(Essay)
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Which of the following statements are not true regarding the model Xy=μ+αi+βj+εyX _ { y } = \mu + \alpha _ { i} + \beta _ { j} + \varepsilon _ { y } where l=1α1=0 and j=1jβj=0?\sum _ { l = 1 } ^ { \prime } \alpha _ { 1 } = 0 \text { and } \sum _ { j = 1 } ^ { j } \beta _ { j } = 0 ?

(Multiple Choice)
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In an experiment to assess the effects of curing time (factor A) and type of mix (factor B) on the compressive strength of hardened cement cubes, three different curing times were used in combination with four different mixes, with three observations obtained for each of the 12 curing time-mix combinations. The resulting sums of squares were computed to be SSA = 30,763.0, SSB = 34,185.6, SSE = 97,436.8, and SST = 205,966.6. a. Construct an ANOVA table. b. Test at level .05 the null hypothesis HoAB: all γijs=0H _ { o A B } : \text { all } \gamma _ { \mathrm { ij } } { } ^ { \prime } s = 0 (no interaction of factors) against HoAB : at least one γij0H _ { o A B } \text { : at least one } \gamma _ { \mathrm { ij } } \neq 0 c. Test at level .05 the null hypothesis HoA:α1=α2=α3=0H _ { o A } : \alpha _ { 1 } = \alpha _ { 2 } = \alpha _ { 3 } = 0 (factor A main effects are absent) against HoA : at least one αi0H _ { o A } \text { : at least one } \alpha _ { i } \neq 0 d. Test HoB:β1=β2=β3=β4=0 ver sus HoB:H _ { o B } : \beta _ { 1 } = \beta _ { 2 } = \beta _ { 3 } = \beta _ { 4 } = 0 \text { ver sus } H _ { o B } : at least one βj0\beta _ { j } \neq 0 using a level .05 test. e. The values of the xˉ100 ’s were xˉ100=4010.88,xˉ200=4029.10, and xˉ300=3960.02\bar { x } _ { 1 00 } \text { 's were } \bar { x } _ { 100 } = 4010.88 , \bar { x } _ { 2 00 } = 4029.10 \text {, and } \bar { x } _ { 300 } = 3960.02 Use Tukey's procedure to investigate significant differences among the three curing times.

(Essay)
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A two-factor experiment where factor A consists of I levels, factor B consists of J levels, and there is only one observation on each of the IJ treatments, can be represented by the model X4=μ+αi+βj+εy where i=1jαi=0 and j=1jβj=0X _ { 4 } = \mu + \alpha _ { i } + \beta _ { j } + \varepsilon _ { y } \text { where } \sum _ { i = 1 } ^ { j} \alpha _ { i } = 0 \text { and } \sum _ { j = 1 } ^ { j } \beta _ { j } = 0 . Which of the following is the correct form in testing the null hypothesis that the different levels of factor A have no effect on true average response?

(Multiple Choice)
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In two-factor ANOVA, additivity means that the difference in true average responses for any two levels of one of the factors is the same for each level of the other factor. When additivity does not hold, we say that there is __________ between the different levels of the factors.

(Short Answer)
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In the three-factor fixed effects model, assume that there are 3 levels for each of the three factors A, B, and C, and 2 observations for each combination of levels of the three factors. Then the number of degrees of freedom for the error sum of squares (SSE) is

(Multiple Choice)
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The current (in μA\mu A ) necessary to produce a certain level of brightness of a television tube was measured for two different types of glass and three different types of phosphor, resulting in the accompanying data: Phosphor Type Glass 1 280,290,285 300,310,295 270,285,290 Type 2 230,235,240 260,240,235 220,225,230 Assuming that both factors are fixed, test HoAB versus HoABH _ { o A B } \text { versus } H _ { oA B } at level .01. Then if HoABH _ { o A B } cannot be rejected, test the two sets of main effect hypotheses.

(Essay)
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An experiment in which there are p factors, each at two levels, is referred to as a

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