Question 1

What condition can make Post Hoc tests less robust?

Accepted Answer

A) Equal group sizes. 
B) Effect sizes. 
C) Outliers and heteroscedasticity. 
D) Homoscedasticity. 
A) Equal group sizes. 
B) Effect sizes. 
C) Outliers and heteroscedasticity. 
D) Homoscedasticity. D

Question 2

Subsequent to obtaining a significant result from an exploratory one-way independent ANOVA, a researcher decided to conduct three t-tests to investigate where the differences between groups lie. Which of the following statements is correct?

Accepted Answer

A) The researcher should accept as statistically significant tests with a probability value of less than 0.016 to avoid making a Type I error. 
B) The researcher should have conducted orthogonal contrasts instead of t-tests to avoid making a Type I error. 
C) This is the correct method to use.The researcher did not make any predictions about which groups will differ before running the experiment, therefore contrasts and post hoc tests cannot be used. 
D) None of these options are correct. 
A) The researcher should accept as statistically significant tests with a probability value of less than 0.016 to avoid making a Type I error. 
B) The researcher should have conducted orthogonal contrasts instead of t-tests to avoid making a Type I error. 
C) This is the correct method to use.The researcher did not make any predictions about which groups will differ before running the experiment, therefore contrasts and post hoc tests cannot be used. 
D) None of these options are correct. A

Question 3

What is the overall effect of an independent variable on a dependent variable known as?

Accepted Answer

A) The interaction effect 
B) The main effect 
C) The direct effect 
D) The indirect effect 
A) The interaction effect 
B) The main effect 
C) The direct effect 
D) The indirect effect B

Question 4

What kind of trend does the following graph show?

Accepted Answer

A) Cubic 
B) Quartic 
C) Quadratic 
D) Linear 
A) Cubic 
B) Quartic 
C) Quadratic 
D) Linear

Question 5

A researcher wanted to see the effects of different learning strategies. A control group simply read the book Discovering Statistics (Book), a second group read the book and completed the 'end of chapter exercises' (Book & Exercises), and a third group read the book, did the end of chapter exercises and also completed the web materials (All Activities). The researcher predicted that the 'all activities' and 'book and exercises' groups would perform better than the book group on a subsequent test, but that the 'book and exercises' group would perform worse than the 'all activities' group. Which coding scheme would test these hypotheses in a set of planned comparisons? (Hint: The sum of weights for a comparison should be zero. If you add up the weights for a given contrast the result should be zero.)

Accepted Answer

A)    
B)    
C)    
D)  $\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $Case Summaries $ { }^{a} $
$\begin{array}{|l|l|r|r|r|}
\hline &{\text { Contrast }} & {\text { Book }} & \begin{array}{c}
\text { Book \& } \
\text { Exercises }
\end{array} & \text { All Activities } \
\hline 1 & \text { Contrast 1 } & 2 & -1 & -1 \
2 & \text { Contrast 2 } & 0 & -1 & -1 \
\hline
\end{array}$

a. Limited to first 100 cases. 
A)    
B)    
C)    
D)  $\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $$\quad $Case Summaries $ { }^{a} $
$\begin{array}{|l|l|r|r|r|}
\hline &{\text { Contrast }} & {\text { Book }} & \begin{array}{c}
\text { Book \& } \
\text { Exercises }
\end{array} & \text { All Activities } \
\hline 1 & \text { Contrast 1 } & 2 & -1 & -1 \
2 & \text { Contrast 2 } & 0 & -1 & -1 \
\hline
\end{array}$

a. Limited to first 100 cases.

Question 6

A psychologist was looking at the effects of an intervention on depression levels. Three groups were used: waiting list control, treatment and post-treatment (a group who had had the treatment 6 months before). 
-Based on the output for these tests, what should the researcher conclude? $\quad $$\quad $Test of Homogeneity of Variances

BDIDIF
$\begin{array}{|c|r|r|r|}
\hline \begin{array}{l}
\text { Levene } \
\text { Statistic }
\end{array} &{\text { df1 }} &{\text { df2 }} & \text { Sig. } \
\hline 4.246 & 2 & 45 & .020 \
\hline
\end{array}$

Accepted Answer

A) The treatment group was significantly different from the control group but not the post-treatment group, and the post-treatment group was significantly different from the control group. 
B) The treatment group was significantly different from the post-treatment and control group, and the post-treatment group was significantly different from the control group. 
C) The treatment group was significantly different from the control group but not the post-treatment group, and the post-treatment group was not significantly different from the control group. 
D) The post hoc tests are inconclusive. 
A) The treatment group was significantly different from the control group but not the post-treatment group, and the post-treatment group was significantly different from the control group. 
B) The treatment group was significantly different from the post-treatment and control group, and the post-treatment group was significantly different from the control group. 
C) The treatment group was significantly different from the control group but not the post-treatment group, and the post-treatment group was not significantly different from the control group. 
D) The post hoc tests are inconclusive.

Question 7

Identify two robust tests for identifying homogeneity.

Accepted Answer

A) Welch's F and Field's F. 
B) Browne-Forsythe F and Kruskal-Wallis F. 
C) Welch's F and Browne-Forsythe F. 
D) Mauchly's F and Field's F. 
A) Welch's F and Field's F. 
B) Browne-Forsythe F and Kruskal-Wallis F. 
C) Welch's F and Browne-Forsythe F. 
D) Mauchly's F and Field's F.

Question 8

What are post hoc tests?

Accepted Answer

A) They are tests, which conduct stepwise contrasts, contrasting all the different combination of groups within an ANOVA, through a comparison of each standard deviation against all the others. 
B) They are tests, which conduct pairwise contrasts, examining all the different combination of groups within an ANOVA, through a comparison of each group's effect size against all the others. 
C) They are tests, which conduct pairwise comparisons, contrasting all the different combination of groups within an ANOVA, through a comparison of each standard error against all the others. 
D) They are tests, which conduct pairwise comparisons, comparing all the different combinations of groups within an ANOVA, through a comparison of each mean against all the others. 
A) They are tests, which conduct stepwise contrasts, contrasting all the different combination of groups within an ANOVA, through a comparison of each standard deviation against all the others. 
B) They are tests, which conduct pairwise contrasts, examining all the different combination of groups within an ANOVA, through a comparison of each group's effect size against all the others. 
C) They are tests, which conduct pairwise comparisons, contrasting all the different combination of groups within an ANOVA, through a comparison of each standard error against all the others. 
D) They are tests, which conduct pairwise comparisons, comparing all the different combinations of groups within an ANOVA, through a comparison of each mean against all the others.

Question 9

When the between-groups variance is a lot larger than the within-groups variance, the F-value is ____ and the likelihood of such a result occurring because of sampling error is _____

Accepted Answer

A) small; low 
B) large; high 
C) large; low 
D) small; high 
A) small; low 
B) large; high 
C) large; low 
D) small; high

Question 10

When conducting a one-way independent ANOVA with three levels on the independent variable, an F-ratio that is large enough to be statistically significant tells us:

Accepted Answer

A) That the model fitted to the data accounts for less variation than extraneous factors, but it doesn't tell us where the differences between groups lie. 
B) That there is a significant three-way interaction. 
C) That all of the differences between means are statistically significant. 
D) That one or more of the differences between means is statistically significant but not where the differences between groups lie. 
A) That the model fitted to the data accounts for less variation than extraneous factors, but it doesn't tell us where the differences between groups lie. 
B) That there is a significant three-way interaction. 
C) That all of the differences between means are statistically significant. 
D) That one or more of the differences between means is statistically significant but not where the differences between groups lie.

Question 11

A sports coach running a junior coaching programme was interested in examining the differences in children's fitness performance scores across four different coaching regimes. She was particularly interested in whether the regime the child was in had a possible influence on the child's fitness performance score. She ran an ANOVA with the predictor variable 'coaching regime', which had four categories, 'Yellow group', 'Green group', 'Pink group' and 'Purple group'; the outcome variable was 'fitness performance score'. Her ANOVA had an F-statistic of 98.12 (p 0.02). How would you interpret her findings?

Accepted Answer

A) There is a significant difference in children's fitness performance score by coaching regime. 
B) There is no significant difference in children's fitness performance score by coaching regime. 
C) There is insufficient information; the results of Post hoc tests are needed. 
D) The results are ambiguous. 
A) There is a significant difference in children's fitness performance score by coaching regime. 
B) There is no significant difference in children's fitness performance score by coaching regime. 
C) There is insufficient information; the results of Post hoc tests are needed. 
D) The results are ambiguous.

Question 12

Of the tests below, which tests that the group means are a better fit of the data than the grand mean?

Accepted Answer

A) Both the repeated-measures and independent ANOVA 
B) The independent ANOVA only 
C) The dependent ANOVA only 
D) Friedman's ANOVA 
A) Both the repeated-measures and independent ANOVA 
B) The independent ANOVA only 
C) The dependent ANOVA only 
D) Friedman's ANOVA

Question 13

The student welfare office was interested in trying to enhance students' exam performance by investigating the effects of various interventions. They took five groups of students before their statistics exams and gave them one of five interventions: (1) a control group just sat in a room contemplating the task ahead; (2) the second group had a yoga class to relax them; (3) the third group were told they would get monetary rewards contingent upon the grade they received in the exam; (4) the fourth group were given beta-blockers to calm their nerves; and (5) the fifth group were encouraged to sit around winding each other up about how much revision they had/hadn't done (a bit like what usually happens). The final percentage obtained in the exam was the dependent variable. Using the critical values for F, how would you report the result in the table below? $$\begin{array} {| l | l l l l |} 
\hline&\text { SS} & \text { Df } & \text { MS } & F \
\hline \text { Madel } & 1213.6 & 4 & 303.4 & 12.43 ^ { * * } \
\text { Residual } & 7079 & 29 & 21.4 & \
\hline \text { Total } & 1921.5 & 33 & & \
\hline
\end{array}$$

Accepted Answer

A) Type of intervention had a significant effect on levels of exam performance, F(4, 29) = 12.43, p .05. C) Type of intervention did not have a significant effect on levels of exam performance, F(4, 33) = 12.43, p > .01. D) Type of intervention had a significant effect on levels of exam performance, F(4, 33) = 12.43, p < .01. A) Type of intervention had a significant effect on levels of exam performance, F(4, 29) = 12.43, p .05. C) Type of intervention did not have a significant effect on levels of exam performance, F(4, 33) = 12.43, p > .01. D) Type of intervention had a significant effect on levels of exam performance, F(4, 33) = 12.43, p < .01.

Question 14

Imagine we conduct a one-way independent ANOVA with four levels on our independent variable and obtain a significant result. Given that we had equal sample sizes, we did not make any predictions about which groups would differ before the experiment and we want guaranteed control over the Type I error rate, which would be the best test to investigate which groups differ?

Accepted Answer

A) Hochberg's GT2 
B) Helmert 
C) Orthogonal contrasts 
D) Bonferroni 
A) Hochberg's GT2 
B) Helmert 
C) Orthogonal contrasts 
D) Bonferroni

Question 15

How can we decide whether our group means are significantly different in an ANOVA?

Accepted Answer

A) By reviewing the standard error. 
B) By reviewing the F-statistic. 
C) By reviewing the Mean. 
D) By reviewing the Z-score. 
A) By reviewing the standard error. 
B) By reviewing the F-statistic. 
C) By reviewing the Mean. 
D) By reviewing the Z-score.

Question 16

Imagine you compare the effectiveness of four different types of stimulant to keep you awake while revising statistics using a one-way ANOVA. The null hypothesis would be that all four treatments have the same effect on the mean time kept awake. How would you interpret the alternative hypothesis?

Accepted Answer

A) All four stimulants have different effects on the mean time spent awake. 
B) At least two of the stimulants will have different effects on the mean time spent awake. 
C) None of the above 
D) Two of the four stimulants have the same effect on the mean time spent awake. 
A) All four stimulants have different effects on the mean time spent awake. 
B) At least two of the stimulants will have different effects on the mean time spent awake. 
C) None of the above 
D) Two of the four stimulants have the same effect on the mean time spent awake.

Question 17

If the differences between group means are large enough, then:

Accepted Answer

A) It is likely that the assumption of sphericity will have been violated. 
B) The assumption of homogeneity of variances is likely to have been violated. 
C) The resulting model will be a better fit of the data than the grand mean. 
D) The resulting model will be a poorer fit of the data than the grand mean. 
A) It is likely that the assumption of sphericity will have been violated. 
B) The assumption of homogeneity of variances is likely to have been violated. 
C) The resulting model will be a better fit of the data than the grand mean. 
D) The resulting model will be a poorer fit of the data than the grand mean.

Question 18

Which of the following is not a rule for conducting orthogonal contrasts?

Accepted Answer

A) The sum of weights for a comparison should not be zero. 
B) The group that is singled out in one comparison should be excluded from any subsequent contrasts. 
C) For a given contrast, the weights assigned to the group(s) in one chunk of variation should be equal to the number of groups in the opposite chunk of variation. 
D) If we give a group a weight of zero then this eliminates that group from all calculations. 
A) The sum of weights for a comparison should not be zero. 
B) The group that is singled out in one comparison should be excluded from any subsequent contrasts. 
C) For a given contrast, the weights assigned to the group(s) in one chunk of variation should be equal to the number of groups in the opposite chunk of variation. 
D) If we give a group a weight of zero then this eliminates that group from all calculations.

Question 19

After an ANOVA you need more analysis to find out which groups differ. When you did not generate specific hypotheses before the experiment use:

Accepted Answer

A) t-tests 
B) Bootstrapping 
C) Post hoc tests 
D) Planned contrasts 
A) t-tests 
B) Bootstrapping 
C) Post hoc tests 
D) Planned contrasts

Question 20

A health researcher was interested in the variation of patient recovery rates across four different treatment programmes. He was particularly interested in whether the treatment programme that the patient was in had a possible influence on the patient's recovery rate. He ran an ANOVA with the predictor variable 'treatment programme', which had three categories, 'Placebo', 'Drug X' and 'Natural'; the outcome variable was 'Patient recovery rate'. His ANOVA had an F-statistic of 98.12 (p 0.02). How would you interpret his findings?

Accepted Answer

A) There is no significant difference in patient recovery rates by treatment programme. 
B) There is insufficient information; the results of Post hoc tests are needed. 
C) There is a significant difference in patient recovery rates by treatment programme. 
D) The results are ambiguous. 
A) There is no significant difference in patient recovery rates by treatment programme. 
B) There is insufficient information; the results of Post hoc tests are needed. 
C) There is a significant difference in patient recovery rates by treatment programme. 
D) The results are ambiguous.

What condition can make Post Hoc tests less robust?

Subsequent to obtaining a significant result from an exploratory one-way independent ANOVA, a researcher decided to conduct three t-tests to investigate where the differences between groups lie. Which of the following statements is correct?

What is the overall effect of an independent variable on a dependent variable known as?

What kind of trend does the following graph show?

Identify two robust tests for identifying homogeneity.

What are post hoc tests?

When the between-groups variance is a lot larger than the within-groups variance, the F-value is and the likelihood of such a result occurring because of sampling error is _

When conducting a one-way independent ANOVA with three levels on the independent variable, an F-ratio that is large enough to be statistically significant tells us:

Of the tests below, which tests that the group means are a better fit of the data than the grand mean?

How can we decide whether our group means are significantly different in an ANOVA?

Imagine you compare the effectiveness of four different types of stimulant to keep you awake while revising statistics using a one-way ANOVA. The null hypothesis would be that all four treatments have the same effect on the mean time kept awake. How would you interpret the alternative hypothesis?

If the differences between group means are large enough, then:

Which of the following is not a rule for conducting orthogonal contrasts?

After an ANOVA you need more analysis to find out which groups differ. When you did not generate specific hypotheses before the experiment use:

Why Is My Evil Lecturer Forcing Me to Learn Statistics

The Spine of Statistics

The Phoenix of Statistics

The IBM Spss Statistics Environment

Exploring Data With Graphs

The Beast of Bias

Non-Parametric Models

Correlation

Regression

Comparing Two Means

Moderation, Mediation and More Regression

GlM 2: Comparing Means Adjusted for Other Predictors Analysis of Covariance

GlM 3: Factorial Designs

GlM 4: Repeated-Measures Designs

GlM 5: Mixed Designs

Multivariate Analysis of Variance Manova

Exploratory Factor Analysis

Categorical Outcomes: Chi-Square and Loglinear Analysis

Categorical Outcomes: Logistic Regression

Multilevel Linear Models

Filters

Exam 12: GlM 1: Comparing Several Independent Means

What condition can make Post Hoc tests less robust?

Subsequent to obtaining a significant result from an exploratory one-way independent ANOVA, a researcher decided to conduct three t-tests to investigate where the differences between groups lie. Which of the following statements is correct?

What is the overall effect of an independent variable on a dependent variable known as?

What kind of trend does the following graph show?

Identify two robust tests for identifying homogeneity.

What are post hoc tests?

When the between-groups variance is a lot larger than the within-groups variance, the F-value is ____ and the likelihood of such a result occurring because of sampling error is _____

When conducting a one-way independent ANOVA with three levels on the independent variable, an F-ratio that is large enough to be statistically significant tells us:

Of the tests below, which tests that the group means are a better fit of the data than the grand mean?

How can we decide whether our group means are significantly different in an ANOVA?

Imagine you compare the effectiveness of four different types of stimulant to keep you awake while revising statistics using a one-way ANOVA. The null hypothesis would be that all four treatments have the same effect on the mean time kept awake. How would you interpret the alternative hypothesis?

If the differences between group means are large enough, then:

Which of the following is not a rule for conducting orthogonal contrasts?

After an ANOVA you need more analysis to find out which groups differ. When you did not generate specific hypotheses before the experiment use:

Why Is My Evil Lecturer Forcing Me to Learn Statistics

The Spine of Statistics

The Phoenix of Statistics

The IBM Spss Statistics Environment

Exploring Data With Graphs

The Beast of Bias

Non-Parametric Models

Correlation

Regression

Comparing Two Means

Moderation, Mediation and More Regression

GlM 2: Comparing Means Adjusted for Other Predictors Analysis of Covariance

GlM 3: Factorial Designs

GlM 4: Repeated-Measures Designs

GlM 5: Mixed Designs

Multivariate Analysis of Variance Manova

Exploratory Factor Analysis

Categorical Outcomes: Chi-Square and Loglinear Analysis

Categorical Outcomes: Logistic Regression

Multilevel Linear Models

Filters

When the between-groups variance is a lot larger than the within-groups variance, the F-value is and the likelihood of such a result occurring because of sampling error is _