PSY 200 Unit 4
The critical cutoffs for a two tailed Tukey HSD test comparing three group means with 11 within-groups degrees of freedom are:
-3.82 and 3.82
Pet preference was compared for four different types of animals (dogs, cats, birds, and fish), using a one-way within-groups ANOVA with seven participants. The standard error was calculated as 0.21. What is the Tukey HSD value when comparing data for birds and fish given the following means for preference: Dogs M=4.43, Cats M=4.18, Birds M=2.73, Fish M=4.07?
-6.38
Using the Bonferroni post hoc test, to make all possible comparisons between the means of three groups while keeping the overall p level at 0.05, what should the p level be for each comparison?
0.017
For a study, a chi-square statistic of 4.42 was calculated. There were 87 participants in total, and 2 degrees of freedom for the first variable and 1 degree of freedom for the second variable. What is the effect size?
0.225
If the p level is 0.05 and the null hypothesis is true, the probability of making a Type 1 error when performing a single hypothesis test is ______, but if three hypothesis tests are performed, then the probability of NOT making a Type 1 error is ______, which means that the probability of making a Type 1 error at least once in these three hypothesis tests is ______.
0.95; 0.857; 0.143
In a z test and a t test, when there is no difference between groups, the test statistic is equal to _____, but in the ANOVA, when there are no differences among groups, the test statistic is equal to _____.
0;1
In a study of simulated juror decision making, Braden-Maguire, Sigal, and Perrino (2005) investigated the type of verdict assigned by study participants after they read a 12-page summary of a case involving a battered woman who had shot and killed her husband. In particular, the researchers manipulated the race of the defendant (African American or Caucasian) and the type of abuse suffered (emotional or physical). The dependent variable was the number of guilty verdicts. What are the degrees of freedom associated with the chi-square analysis of these data?
1
Pet preference was compared for four different types of animals (dogs, cats, birds, and fish), using a one-way within-groups ANOVA with seven participants. The standard error was calculated as 0.21. What is the Tukey HSD value when comparing data for dogs and cats given the following means for preference: Dogs M=4.43, Cats M=4.18, Birds M=2.73, Fish M=4.07?
1.190
A one-way within-groups ANOVA is used when there are ______ than 2 independent variable(s) with two or ______levels.
1;more
A dependent-samples t test is used when there are ______ groups, and a within-groups ANOVA is used when there are at least ______ groups.
2;3
What is the critical cutoff for F at a p level of 0.05 if the following degrees of freedom were calculated for a one-way within-groups ANOVA: dfbetween=4, dfsubjects=4, dftotal=24, dfwithin=16?
3.01
With a p level of 0.05, a chi-square test for goodness-of-fit for which there are 5 categories would have _____ degrees of freedom, and the critical value for the chi square would be _____.
4; 9.49
Pet preference was compared for four different types of animals (dogs, cats, birds, and fish), using a one-way within-groups ANOVA with seven participants. The standard error was calculated as 0.21. What is the Tukey HSD value when comparing data for dogs and birds given the following means for preference: Dogs M=4.43, Cats M=4.18, Birds M=2.73, Fish M=4.07?
8.10
If an F statistic is negative, which of these is true?
There has been a calculation error
Which statement accurately captures why within-groups designs are preferred over between-groups designs?
Variability due to participants' differences is held constant across levels of the independent variable in the within-groups design, resulting in less within-groups variability.
What is the formula for the Kruskal-Wallis H test?
[12/N(N+1)][Σn(M-GM)^2]
The nonparametric equivalent of the one-way between-groups ANOVA is the: a. Kruskal-Wallis H test. b. Mann-Whitney U test. c. chi square. d. Wilcoxon signed-rank test.
a. Kruskal-Wallis H test.
You are interested in attempting to replicate the results of a 1973 study by Belmont and Marolla that found a negative correlation between birth order and IQ. You collect the necessary data using students in your school's participant pool. Which technique would you use to analyze your data? a. Spearman rank-order correlation coefficient b. Pearson correlation coefficient c. Mann-Whitney U test d. Kruskal-Wallis H test
a. Spearman rank-order correlation coefficient
When transforming scale data to ordinal data, if two people have exactly the same score, what is their rank? a. They receive the average of the two ranks they would hold if the scores were different. b. They receive the same, lower rank. c. They receive the highest and second-highest rank. d. They receive the lowest and the second-lowest rank.
a. They receive the average of the two ranks they would hold if the scores were different.
To calculate a Spearman rank-order correlation coefficient, first convert both variables to ranks. After that: a. compute the difference between each pair of ranks. b. sum the ranks. c. square the ranks. d. subtract the mean from each score.
a. compute the difference between each pair of ranks.
The assumptions of the Kruskal-Wallis H test are that the: a. data are ordinal and participants are randomly selected. b. data are ordinal, participants are randomly selected, and the population distribution of ranks is symmetric. c. data are scale and participants are randomly selected. d. participants are randomly selected and the population distribution is symmetric.
a. data are ordinal and participants are randomly selected.
Does the number of points a person earns on the final exam in statistics depend on whether the person is a member of a Greek organization? In three statistics classes, data is collected on the final exam points of students belonging to Greek organizations and of students who do not belong. Which technique would be used to analyze the data? a. independent-samples t test b. paired-samples t test c. Wilcoxon signed-rank test d. Mann-Whitney U test
a. independent-samples t test
Bootstrapping is used on a sample of data with the following values: 520, 515, 480, 420, 610, 470, 420, and 630. The confidence interval created through bootstrapping will be centered around what value? a. mean of the original sample b. mean of the distribution of sample means c. zero d. mean of the test
a. mean of the original sample
To determine the critical cutoff for Mann-Whitney U, which of these must be known? a. sample size of both groups b. degrees of freedom for both groups c. degrees of freedom for the smallest group d. size of the population
a. sample size of both groups
When using the Wilcoxon signed-rank test, reject the null hypothesis only when the _____ of the two calculated statistics is equal to or _____ than the critical value. a. smaller; less b. larger; less c. smaller; greater d. larger; greater
a. smaller; less
The assumptions of the Wilcoxon signed-rank test are that: a. the difference between pairs of scores can be ranked, participants are randomly selected, and the population distribution of differences is symmetric. b. the mean difference between pairs of scores is 0, participants are randomly selected, and the population is symmetric. c. participants are randomly selected and the population is symmetric. d. the mean of the population of difference scores is 0 and its distribution is symmetric.
a. the difference between pairs of scores can be ranked, participants are randomly selected, and the population distribution of differences is symmetric.
When using matched groups for a one-way within-groups ANOVA, a researcher should "match" participants on:
all of the variables that the researcher wants to control
If the cutoff q statistic is 4.96, with a P level of 0.05, which of these would be significant?
an HSD of 5.2
A sample of 10 men and 12 women are compared on their ranked life satisfaction. What is the critical cutoff for a two-tailed Mann-Whitney U test comparing these groups? a. 30 b. 29 c. 23 d. 20
b. 29
Using a p level of 0.05, a researcher performed the Wilcoxon signed-rank test with a sample size of 16 and found that the sum of the ranks for positive differences was 36 and the sum of the ranks for negative differences was 100. Which statement accurately describes the results of the hypothesis test for these data? a. Reject the null because the test statistics sum to above 100. b. The test statistic is larger than the critical cutoff, which is 29, so fail to reject the null hypothesis. c. The values exceed the critical cutoff, so reject the null hypothesis. d. Fail to reject the null hypothesis because 36 is less than 100.
b. The test statistic is larger than the critical cutoff, which is 29, so fail to reject the null hypothesis.
If one rejects the null hypothesis when using the Kruskal-Wallis H test, then: a. all the groups differ significantly from one another. b. at least one of the groups differs significantly from another, but you do not know which one. c. the group ranks are similar. d. the largest difference between a ranked pair is at least two times the smallest difference.
b. at least one of the groups differs significantly from another, but you do not know which one
The process of representing an entire population of data by repeatedly sampling from the original sample is called: a. repeated sampling. b. bootstrapping. c. transformation. d. null hypothesis testing.
b. bootstrapping.
One should reject the null hypothesis using the Kruskal-Wallis H test when the calculated H statistic is _____ the critical value. a. less than or equal to b. greater than c. five times d. less than five times
b. greater than
Melanie is interested in whether science fiction movies typically get higher star ratings (on a five-star scale) than dramas. What kind of statistical test could be used to address this question? a. parametric test b. nonparametric test c. correlation d. independent-samples t test
b. nonparametric test
To use a nonparametric test despite having scale data, transform the data from scale to: a. nominal. b. ordinal. c. the square root of the scale values. d. the square root of the ratio values.
b. ordinal.
One of the assumptions of the Wilcoxon signed-rank test is that the distribution of the population of difference scores is: a. skewed. b. symmetric. c. bimodal. d. normal.
b. symmetric.
One of the assumptions of the Mann-Whitney U test is that there are no ties. If there are ties in the data set: a. do not use the Mann-Whitney U test. b. use the Mann-Whitney U test if there are just a few ties as it is robust to violations of this assumption. c. use the Mann-Whitney U test anyway, even if you have lots of ties in your data. d. use the Kruskal-Wallis H test instead.
b. use the Mann-Whitney U test if there are just a few ties as it is robust to violations of this assumption.
R2, the effect size for ANOVA, is calculated as a ratio of:
between-groups sums of squares to total sum of squares
A Spearman's correlation coefficient can range from _____ to _____. a. 0; 1.00 b. -1.00; 0 c. -1.00; 1.00 d. -10.00; 10.00
c. -1.00; 1.00
Four different sports teams are compared for the athleticism of their members. The data on athleticism is available as ranks only. What would be the critical cutoff for the Kruskal-Wallis test on these data, assuming a p level of 0.05? a. 3.841 b. 5.992 c. 7.815 d. 9.488
c. 7.815
Using a p level of 0.05, a researcher performed the Wilcoxon signed-rank test with a sample size of 10 and found that S R+ = 3 and S R- = 9. Which statement accurately describes the results of this hypothesis test? a. Because T = 9, the researcher failed to reject the null hypothesis. b. Because T = 9, the researcher rejected the null hypothesis. c. Because T = 3, the researcher rejected the null hypothesis. d. Because T = 3, the researcher failed to reject the null hypothesis.
c. Because T = 3, the researcher rejected the null hypothesis.
A correlation of 0.56 is found between class rank and student likeability. What can be concluded based on this correlation? a. Good grades cause increases in popularity. b. Class rank is predictive of academic performance. c. Low class ranks tend to be associated with low likeability ranks, and high class ranks tend to be associated with high ranks for likeability. d. High likeability is associated with low class rank, and low likeability is associated with high class rank.
c. Low class ranks tend to be associated with low likeability ranks, and high class ranks tend to be associated with high ranks for likeability.
The Mann-Whitney U test would be used in which of these examples? a. Ranked job satisfaction was compared for members of five different work teams. b. Ranked job satisfaction was compared for the same eight women before and after they had a child. c. Ranked job satisfaction was compared for males and females at a local business. d. Job satisfaction as a scale variable is compared for three different work teams.
c. Ranked job satisfaction was compared for males and females at a local business.
Blake is interested in training for his first marathon and wants to determine whether the finishing time of non-elite marathon runners depends on the type of training program used. There are three training programs he is interested in comparing: Hal Higdon's, Jeff Galloway's, and Art Liberman's. Blake is able to track down 30 runners, 10 of whom have done each of the training programs. Blake asks the runners for their marathon finishing times. What statistic should he use to analyze his data? a. Spearman rank-order correlation coefficient b. Mann-Whitney U test c. one-way ANOVA d. Kruskal-Wallis H test
c. one-way ANOVA
Nonparametric tests are usually used when the sample data are: a. nominal or ordinal. b. nominal or extremely skewed. c. ordinal or extremely skewed. d. ordinal or when participants have been randomly selected.
c. ordinal or extremely skewed
The sample size for the Wilcoxon signed-rank test is: a. equal to the number of participants. b. two times the number of participants. c. the number of difference scores that are not 0. d. N - 1.
c. the number of difference scores that are not 0.
The z, t, and F distributions have something in common- the denominator of the test statistic:
contains a measure of difference within the various groups.
The paired ranks for a Wilcoxon signed-rank test were: 1, - 1; 2, - 2; 5, - 3; 3, - 5; 4, - 4. What is the sample size for this test? a. 5 b. 4 c. 3 d. 2
d. 2
A researcher is transforming finishing times from a 5K race into ordinal data and has the following scores in minutes: 12.2, 16.5, 13.4, 17.8, 13.4, 13.4, and 18.6. If the researcher ranks from fastest to slowest, what would be the rank of the three people with a finish time of 13.4? a. 5 b. 4 c. 3.5 d. 3
d. 3
Blake is interested in training for his first marathon and wants to determine whether the finishing place of non-elite marathon runners depends on the type of training program used. There are three training programs he is interested in comparing: Hal Higdon's, Jeff Galloway's, and Art Liberman's. Blake is able to track down 30 runners, 10 of whom have done each of the training programs. Blake asks the runners how they placed in the marathon. What statistic should he use to analyze his data? a. Spearman rank-order correlation coefficient b. Mann-Whitney U test c. one-way ANOVA d. Kruskal-Wallis H test
d. Kruskal-Wallis H test
Now that you are an adult, you decide to test one of the truisms passed along by your mother: "Cheaters never win in the end." You randomly assign a group of 20 children to either cheat or to play fair on a scavenger hunt. You then rank the children by how many items they were able to get during the scavenger hunt. Which technique would you use to analyze the data to determine whether cheaters finish differently than non-cheaters? a. independent-samples t test b. paired-samples t test c. Wilcoxon signed-rank test d. Mann-Whitney U test
d. Mann-Whitney U test
A researcher wants to examine the relation between class rank and popularity among peers. Class rank is provided by the school and includes each student's rank in order. The researcher assesses popularity using a likability measure that provides scale data. What statistic should be used to assess this relation? a. chi-square test for goodness-of-fit b. independent-samples t test c. Wilcoxon signed-rank test d. Spearman rank-order correlation coefficient
d. Spearman rank-order correlation coefficient
The nonparametric equivalent of the Pearson correlation coefficient is the: a. Kruskal-Wallis H test. b. chi-square. c. Wilcoxon signed-rank test. d. Spearman rank-order correlation coefficient.
d. Spearman rank-order correlation coefficient.
The comparison distribution for the Wilcoxon signed-rank test is the _____ distribution. a. t b. F c. z d. T
d. T
The nonparametric equivalent of the paired-samples t test is the: a. Kruskal-Wallis H test. b. Mann-Whitney U test. c. chi square. d. Wilcoxon signed-rank test.
d. Wilcoxon signed-rank test.
The H distribution for the Kruskal-Wallis H test is very close to the _____ distribution, so the latter is often used for determining the critical values for the Kruskal-Wallis H test. a. F b. t c. T d. chi-square
d. chi-square
A Spearman correlation of rs = -0.30 between birth order and IQ means that: a. having a lower birth order causes a person to have a lower IQ. b. people with lower birth orders tend to have lower IQs. c. having a lower birth order causes a person to have a higher IQ. d. people with lower birth orders tend to have higher IQs.
d. people with lower birth orders tend to have higher IQs.
The process of bootstrapping requires: a. sampling without replacement. b. access to the entire population of scores. c. performing a log transformation of all scores. d. sampling with replacement.
d. sampling with replacement.
The benefits of the within-groups design are seen in the calculation of the F statistic in that the:
denominator is smaller, resulting in a larger F statistic
If between-groups variance is much larger than within-groups variance, we infer that the sample means are ______ one another, and we ______ the null hypothesis.
different from, reject
The F ratio is calculated by:
dividing a measure of between-groups variability by a measure of within-groups variability.
Within-groups degrees of freedom is calculated by:
for each condition, subtracting 1 from the number of subjects in that group and then adding together the totals for all the groups.
______ degrees of freedom must be calculated in a within-groups ANOVA
four
Violation of the assumption that samples are randomly selected affects researchers' ability to:
generalize the results of a study beyond the sample
To calculate the total sum of square for the one-way within-groups ANOVA, each score's deviation from the ______ is squared and summed.
grand mean
For two nominal variables, the appropriate statistical test to use is a chi-square test for:
independence.
Cohen's d cannot be used as a measure of effect size for ANOVA because:
it can only compare two means
According to Cohen's conventions, an R2 of 0.19 is considered to be a(n) ______ effect size.
large
According to Cohen's conventions, an effect size of 0.29 for a one-way within-groups ANOVA is considered to be:
large
The grand mean is the:
mean of every score in the study, regardless of the sample
According to Cohen's conventions, an effect size of 0.056 for a one-way within-groups ANOVA is considered to be:
medium
The less overlap there is among sample distributions, the:
more confident we are that the samples represent true differences in the population
A researcher wonders whether talking to plants keeps them from dying, and conducts a study in which he talks to one group of five plants and do not talk to a second group of five plants. After two weeks the researcher records how many plants have died in each group. This number is a _____ dependent variable, which means that the data can be analyzed using a _____ test.
nominal; nonparametric
A researcher wants to examine people's preference for pets by having 10 people act as "foster owner's" for four different types of family pets: dogs, cats, birds, and fish. The participants will foster each type of pet for one week, and a scale measure will be used to assess preference. Which research design should be used?
one-way within-groups ANOVA
The one-way within-groups design can be viewed as an extension of which other research design because of its ability to analyze data from more groups?
paired-samples t test
What is the formula for the Spearman's correlation coefficient?
r2 = 1 - 6(ΣD^2)/N(N^2 - 1)
The assumptions of ANOVA are that samples are selected:
randomly, the population distribution is normal, and the samples come from populations with equal variances
A post hoc test is warranted when one:
rejects the null hypothesis and there are more than two groups
According to Cohen's conventions, an R2 of 0.02 is considered to be a(n) ______ effect size.
small
According to Cohen's conventions, an effect size of 0.019 for a one-way within-groups ANOVA is considered to be:
small
If there are only two samples and sample size is infinity, then the F Distribution is the:
square of the z distribution
Between-groups degrees of freedom is calculated by:
subtracting 1 from the total number of groups in the study.
One drawback of many nonparametric tests is that:
there is no way of calculating effect sizes.
What types of designs are normally preferred to reduce variability by reducing individual differences?
within-groups designs
A measure of variability that is essentially an average of the sample variance is:
within-groups variance
In which situation would it be necessary to use a between-groups ANOVA?
A researcher is interested in the effects of distraction on driving performance and randomly assigns participants to one of three distraction groups
Given a scale dependent variable and a nominal independent variable with three or more levels, a(n) _____ could be used to analyze the data.
ANOVA
Pet preference was compared for four different types of animals (dogs, cats, birds, and fish), using a one-way within-groups ANOVA with seven participants. The standard error was calculated as 0.21. A significant F test indicates that there are differences between the groups. What post hoc tests are you most interested in performing given these group means: Dogs M=4.43, Cats M=4.18, Birds M=2.73, Fish M=4.07?
Comparisons of preference for birds with the other groups, because the mean is noticeably lower
The statistic for reporting the effect size of a chi square is:
Cramer's V or ϕ.
Changes in within-groups variance result in changes in the ______ of the F ratio.
Denominator
An F statistic calculated on 2 and 26 degrees of freedom equals 2.23. Which decision should be made about a hypothesis tested at the p=0.05?
Fail to reject the null hypothesis and conclude no significant differences are indicated among the groups.
Which F statistic represents a new calculation as part of the within-groups ANOVA?
Fsubjects
F is obtained by dividing _____ by _____.
MSbetween/MSwithin
What's the correct formula for between-groups degrees of freedom?
Ngroups-1
A researcher studying weight loss among overweight teenage girls wants to use a matched groups design to assess the effectiveness of three different diets. On which variable is it MOST important to match the participants?
Percent of body fat
Pet preference was compared for four different types of animals (dogs, cats, birds, and fish), using a one-way within-groups ANOVA with seven participants. The standard error was calculated as 0.21. Where are the significant effects for preference among these groups, given the following means for preference: Dogs M=4.43, Cats M=4.18, Birds M=2.73, Fish M=4.07?
Preference for birds in significantly lower than for the other three groups, and there are no other differences among the mean preferences.
The proportion of variance in the dependent variable that is accounted for by the independent variable is ______.
R2
MSbetween is obtained by dividing:
SSbetween by dfbetween
Legal researchers were interested in whether a rape defendant's perceived guilt depends on the type of argument introduced by his defense attorney. Researchers classified each defense by whether or not it introduced the idea that the female victim was asking for the encounter—the "she shouldn't have worn that short skirt" defense. In a simulated juror situation, the researchers asked each of the 20 participating mock jurors to rate the guilt of the defendant on a scale from 1 to 7. This score is a _____ dependent variable, which means that the data can be analyzed using a _____ test.
Scale; parametric
One danger of reporting relative risk or relative likelihood information rather than frequencies is that:
The base rate occurrence of an event is not reported, and the data can be misleading.
