Deck 19: Analysis of Variance and Experimental Design

Question 1

In a designed experiment, researchers control for various factors such as age, gender, or socioeconomic status.

Answer 1

True

Question 2

Priti is wondering whether time of day impacts worker productivity. She randomly chooses 25 workers from each of the three shifts her company runs. The design of this study is:

A) even
B) balanced
C) unbalanced
D) observational

Answer 2

balanced

Question 3

An observational study:

A) analyzes data already available
B) makes it possible to rule out factors over which the researcher has no control for the observed effects
C) examines individuals that have been selected by the researchers
D) allows researchers to control for all extraneous factors

Answer 3

analyzes data already available

Question 4

Contrast is the unavoidable confusion of some effects with others in an incomplete experimental design.

Question 5

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Mook Corp. has utilized three different types of training for its employees. The company would like to determine whether or not there are differences in the effectiveness (in terms of worker productivity) across the training programs. The one-way ANOVA results are in the table. Suppose Mook Corp. was interested in running a two-way ANOVA. What other factors might you recommend they include in the test?

Question 6

In two-way ANOVA, a single variable is measured at various levels of a single factor.

Question 7

Which p-value from a two-way ANOVA table indicates an effect that is not statistically significant?

A) 0.000
B) 0.011
C) 0.047
D) 0.110

Question 8

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Mook Corp. has utilized three different types of training for its employees. The company would like to determine whether or not there are differences in the effectiveness (in terms of worker productivity) across the training programs. What does the ANOVA output in the accompanying figure indicate?

Question 9

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Mook Corp. has utilized three different types of training for its employees. The company would like to determine whether or not there are differences in the effectiveness (in terms of worker productivity) across the training programs. What is the alternate hypothesis for the ANOVA test in the accompanying figure?

Question 10

In a one-way ANOVA test, we conclude there are differences across population means if the:

A) between variation is small relative to the within variation
B) between variation and within variation are equal
C) between variation is large relative to the within variation
D) between variation equals zero

Question 11

In a full factorial design, researchers assign experimental units to each treatment level combination.

Question 12

Interactions:

A) indicate patterns of differences in means that could not be guessed from the main effects alone
B) occur only in one-way ANOVA tests
C) occur when the effect of one factor on the dependent variable is independent of the level of other factors
D) indicate the effect of one factor on the dependent variable is the same regardless of the level of the other factors

Question 13

Moriah runs a one-way ANOVA to test differences in means in delivery time. The SSB is 109,400 and the total sum of squares is 715,460. What is the value of the SSW?

A) -606,060
B) 218,800
C) 606,060
D) 824,860

Question 14

The smaller the p-value in an ANOVA table, the greater the likelihood that the effect:

A) is statistically insignificant
B) will be ignored
C) is statistically significant
D) has no practical impact

Question 15

What is one assumption of two-way ANOVA tests?

A) The distribution is not normal and the variances are different across combinations.
B) The distribution is normal and the variance at any particular combination is the same as any other combination.
C) The distribution is not normal and the variance at any particular combination is the same as any other combination.
D) The distribution is normal and the variances are different across combinations.

Question 16

Samples with large within variation have boxplots with:

A) wide boxes and long lines extending from them
B) wide boxes and no lines extending from them
C) short boxes and no lines extending from them
D) short boxes and short lines extending from them

Question 17

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Mook Corp. has utilized three different types of training for its employees. The company would like to determine whether or not there are differences in the effectiveness (in terms of worker productivity) across the training programs. Using information from the table, determine the value of the SSB. What does it measure?

Question 18

Jeremiah is testing the impact of different fertilizers on crop yields. Six different fertilizers have been applied to one field. Suppose he uses an ANOVA to test whether or not there are differences in yields. How many treatments are in this test?

A) zero
B) one
C) five
D) six

Question 19

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Mook Corp. has utilized three different types of training for its employees. The company would like to determine whether or not there are differences in the effectiveness (in terms of worker productivity) across the training programs. The table includes one-way ANOVA results. What is the logical next step once Mook Corp. has identified that workers attending different training programs have different productivity levels?

Question 20

The null hypothesis that indicates there are no differences in population means across levels is H₀: µ₁= µ₂=… µ_J.