Psych Stats Exam 3

If p is .05 or greater, then you will say:

"Groups were similar" or "groups did not differ"

If p<.05, then you will say that there is a

"statistically significant difference between groups"

Using a two-tailed at a .05 level of significance, what are the critical values for the normal approximation for the Wilcoxon signed-ranks T test?

+-1.96

The _______________ of the chi-square test statistic accounts for the relative size of a discrepancy between observed and expected frequencies

denominator

scores obtained by subtracting paired scores for two related samples are called:

difference scores

the test statistic compares the _________between observed and expected frequencies

discrepancy

The variance cannot be used to analyze ranked data because ordinal data do not convey

distance

a researcher wants to study differences in mood due to listening to music. before conducting the study, she has participants report how often they listen to music (in minutes) per week. Participants were matched based on their responses, and differences in mood between matched pairs of participants were computed. What type of strategy was used to match participants?

experimental manipulation

A researcher finds that 8 scores fall above the median, 1 equals the median, and 1 falls below the median. What is the p value for a one-sample sign test?

.055

Using a sample of 80 participants, a researcher computes the following test statistic for a chi-square test for independence: Xsquared(1)=4.05. What is the effect size using the phi coefficient?

.23

a researcher computes the following test statistic for a related-samples t test: t(28)= 2.97, p < .05. What is the proportion of variance for this test using the formula for eta-squared?

.24

a researcher conducts a study using the one-way between-subjects ANOVA. She computes SSbg=180 and SSe=520. What is the effect size for this test using eta-squared?

.26

a researcher computes the following test statistic for a related-samples t test: t(22) = 3.14, p < .05. What is the proportion of variance for this test using the formula for omega-squared?

.28 t2 - 1 ------- t2 + df

The test statistic equals___________ when the observed and expected frequencies are the same

0

a researcher selects two related with a mean difference of 6.3. If the standard deviation of the difference scores is 7.2, then what is the effect size using the estimated Cohen's d formula?

0.88 6.3 M ---- ---- 7.2 sD

The frequency observed of individuals preferring Product A is 32, and the number preferring Product B is 40. If the frequency expected is based on the null hypothesis that p = .50 for each product, then what is the value of the test statistic?

0.89

What is the value of the test statistic for the normal approximation for the Mann-Whitney U test if U=16, uU=10.50, and qU=2.80?

1.96

A researcher compares differences in aptitude before and after a treatment. He subtracts pairs of scores from each group and finds that 12 difference scores are positive, 2 equals zero, and 1 is negative. What is the value of the test statistic for a related-samples sign test?

12

The count or frequency of participants recorded in each category or at each level of the categorial variable is called:

frequency observed

A researcher finds that 15 scores fall above the median, 1 equals the median, and 4 fall below the median. What is the value of the test statistic for a one-sample sign test?

15

a group of 20 participants is observed two times. The related-samples t test for this study will have a degree(s) of freedom equal to:

19

A researcher counts the number of students who agree, disagree, or are indifferent concerning a recent school policy change. What are the degrees of freedom for this chi-square goodness-of-fit test?

2

A researcher tests for the relationship between attendance for an exam (absent, tardy, on time) and living arrangement (on campus, commuter). What are the degrees of freedom for this chi-square test for independence?

2

What are the degrees of freedom for a chi square goodness of fit test with k = 3?

2

The frequency observed in each of four categories is 28, 30, 26, and 20. If the frequency expected is based on the null hypothesis that p = .25 for each category, then what is the value of the test statistic?

2.15

What is the degrees of freedom denominator for a study with n = 10 in each of three groups?

27 (30-3)

what is the degrees of freedom numerator for a study with n = 12 in each of four groups?

3

A researcher tests for the relationship between grades on an exam (passing, failing) and whether students took all prerequisite courses (yes, no). What is the critical value for this chi-square test for independence at a .05 level of significance?

3.84

A researcher reports that alertness in the classroom varies by the intensity of lighting in the room, F(3,36) = 3.96, p < .05. How many light intensity groups were observed in this study?

4

The size of an expected frequency should never be smaller than _______ in given category

5

a researcher computes a significant one-way between-subjects ANOVA with 10 participants in each group and MSe=32.4 and dfe= 27. What is the critical value for Fisher's LSD at a .05 level of significance of each pairwise comparison?

5.2

A researcher computes a significant one-way between-subjects ANOVA with eight participants in each of four groups and MSe = 18.1 and dfe= 28. What is the critical value for Tukey's HSD at a .05 level of significance for each pairwise comparison?

5.8

What are the degrees of freedom for a chi-square test for independence with k1=3 and k2 = 4?

6

The frequencies observed for the number of participants working full- or part-time and eating a good or poor diet are given in the table. What is the value of the test statistic for a chi-square test for independence?

6.27

Using a between-subjects design, a researcher reports that emotional responses varied by the type of stressor in a controlled environment, F (4,55) = 6.01, p < .05. How many participants were observed in this study?

60

A researcher tests for differences between four groups with 10 participants observed in each groups (N=40). The test statistic for the Kruskal-Wallis H test = 8.33. What is the decision using a .05 level of significance?

7.28

What is the critical value for a chi square goodness of fit test at a .05 level of significance when k = 4?

7.81

What is the critical value for a chi square test for independence at a .05 level of significance when k1=2 and k2=4?

7.81

A researcher had participants rank the importance of five economic issue was ranked first was recorded. What is the critical value for this chi-square goodness of fit test at a .05 level of significance?

9.49

When the levels of one or more categorical variables are greater than two, we use ________ to estimate effect size?

Cramer's V

Which post hoc test is associated with the greatest power to detect an effect?

Fisher's LSD test

A statistical procedure used to determine whether the total ranks in two or more groups are significantly different when the same participants are observed in each group is called the:

Friedman test

A statistical procedure used to determine whether the total ranks in two or more independent groups are significantly different is called the:

Kruskal-Wallis H test

A statistical procedure used to determine whether the dispersion of ranks in two independent groups is equal is called the:

Mann-Whitney U test

___________ are hypothesis tests are used (1) to test hypotheses that do not make inferences about parameters in a population, (2) to test hypotheses about data that can have any type of distribution, and (3) to analyze data on a nominal or ordinal scale of measurement.

Nonparametric

____________ are hypothesis tests that are used to test hypotheses about parameters in a population in which the data in the population are normally distributed and measured on an interval or ratio scale measurement.

Parametric

using a repeated-measures design, Researcher A computes the following test statistic, t(22) = 1.980, and decides to reject the null hypothesis. Using a matched-pairs design, Researcher B computes the same test statistic, t(22)= 1.980, but decides to retain the null hypothesis. Which of the following can explain why this occurred?

Researcher A computed a one-tailed test; Researcher B computed a two-tailed test

Two (A and B) measure the same mean difference between two related groups using the same sample size. The only difference is that the estimated standard error for difference scores is larger for data for Researcher A than for the data of Researcher B. Which researcher will compute a larger test statistic for a related-samples t test?

Researcher B- because A has standard error, A will compute larger test statistic for related samples test

which of the following is reported only with a related-samples t test and not for any other type of t test?

THE SAME INFO IS REPORTED FOR ALL T TESTS the test statistic, the p value, the degrees of freedom

Using the Wilcoxon signed ranks T test, the _________ the value of the test statistic, the more likely the decision will be to reject the null hypothesis

smaller

A statistical procedure used to determine whether the total ranks in two related groups are significantly different is called the:

Wilcoxon signed-ranks =T test

the sample means and the standard error or the standard deviations measured in the study can be ported in:

a figure, a table, the main text

TO interpret a significant chi-square goodness of fit test, we compare observed and expected frequencies:

at each level of the categorical variable

difference scores are computed ___________ we compute the test statistic for the related-samples t test

before

which of the following is a source of variation in the one-way between-subjects ANOVA?

between-groups variation

with smaller sample sizes, we make a decision for the sign test using probabilities for outcomes in a __________ distribution

binominal

Which of the following is a type of repeated-measures design?

both pre-post design and within-subjects design

how does selecting related samples increase the power to detect an effect?

by reducing the estimate for standard error

The test statistic for the chi-square test for independence is the same as that for what other hypothesis test?

chi-square goodness-of-fit

How does measuring ranked data increase the power to detect an effect for skewed data sets?

converting data to ranks minimizes variability caused by outliers

Which of the following is a strategy that can be used when the size of an expected frequency is smaller than 5 in a given category?

increase the sample size so that it is five times larger than the number of levels of the categorial variable and increase the number of levels of categorical variable so that k is greater than 4

Violating the assumption of homogeneity of variance can:

inflate the value of the variance in the numerator of the test statistic and increase the likelihood of committing a type I error

How does selecting related samples minimize the estimate for standard error?

it changes the level of significance for a hypothesis test and it eliminates the between-persons source of error

Three advantages for selecting related samples include each of the following except:

it decreases the likelihood of a type I error

Why is the value of p equal to .50 in the formula for te normal approximation for the sign test, z = x -np ___________ `/np(1-p)

it is the value stated by the null hypothesis

A researcher compares differences in personality traits among pairs of identical twins. What type of research design did the researcher use?

matched-pairs design

Cramer's V= .25 IF the degrees of freedom smaller are 2, then what is the size of this effect?

medium

Nonparametric tests are alternatives to parametric tests that are used to analyze data on which scales of measurement?

nominal and ordinal

With larger samples, a binominal distribution approximates a ___________ distribution

normal

Which of the following is an assumption of the one-way between-subjects ANOVA?

normality, random sampling, homogeneity of variance

Which of the following is a key assumption for the chi-square test?

observed frequencies are recorded indepently

Which measure of proportion of variance is the most conservative estimate?

omega squred

a statistical procedure used to test hypotheses for one factor with two or more levels concerning the variance among group means, where different participants are observed at each level of a factor, is called the:

one-way between-subject ANOVA

The Kruskal-Wallis H test is a nonparamentric alternative to which hypothesis test?

one-way between-subjects ANOVA

The Friedman test is a nonparametric alternative to which hypothesis test?

one-way within-subjects ANOVA

The null hypothesis for the normal approximation for the Wilcoxon signed-ranks T test is that:

positive and negative difference scores are associated with equal ranks

an advantage of computing difference scores in the related-samples t test is that it:

reduces variability, reduces standard error, increases power

A researcher reports the following for a chi-square goodness of fit test: Xsquared(3)=9.12. What is the decision for this test?

reject the null hypothesis

The test statistic for a Wilcoxon signed-ranks T test is T=71 using a sample of 24 participants. What is the decision for a two-tailed test at a .05 level of significance?

reject the null hypothesis

a researcher measures scores in two groups (n= 12 in each group) with M1 = 9.8 and M2 = 4.8. In this study, the estimated standard error for difference scores is 2.0. What is the decision for a related-samples t test using a two-tailed test at a .05 level of significance?

reject the null hypothesis

a statistical procedure used to test hypotheses concerning two related samples selected from populations in which the variance in one or both populations is unknown is called a:

related-samples t test

A researcher observes the same group of participants in the morning and again at night. What type of research design did the researcher use?

repeated-measures design

A researcher compares differences in ratings for two types of toys. She subtratcs pairs of ratings given by each participant and finds that 10 difference scores are positive, 2 equal zero, and 2 are negative. What is the decision for a related-samples sign test at a .05 level of significance?

retain the null hypothesis

The test statistic for a MAnn-Whitney U test is U=37 using a sample of 11 participants in each group. What is the decision for a two-tailed test at a .05 level of significance?

retain the null hypothesis

The null hypothesis for the normal approximation for the Mann-Whitney U test is that:

scores are evenly dispersed between groups

The _______ is a statistical procedure used to determine the binomial probability that an observed number of scores fall above and below the median (one sample) or are positive and negative (related samples)

sign test

Using the Mann-Whitney U test, the _________________the value of the test statistic, the more likely the decision will be to reject the null hypothesis

smaller

a researcher conducts 2 studies. The sum of squares between groups is larger in study 1 compared with study 2; the sum of squares total is smaller in study 1 compared with study 2. In which study will eta-squared be smaller?

study 2

A researcher computes a related-samples t test using the following data: M1 = 16, M2= 13, sD=8.0, and nD=16. What is the value of the test statistic using these data if the null hypothesis is that there is no mean difference?

t(15) = 1.50

Which of the following is reported for a Friedman test but not for a Man-Whitney U test?

the degrees of freedom

A researcher reports the following for a chi square test for independence: Xsquared(4)=6.02, p < .05 (o=/.18). Assuming that both categorical factors had three levels, which value is not possible in this summary?

the estimate of effect size

A researcher had participants engage in a conversation with a confederate who was dressed in casual, informal, or formal clothes. A one-way between-subjects ANOVA showed that duration of eye contact in the conversation significantly varied by type of dress. If the mean duration of eye contact (in seconds) in each group was 14(casual), 10(informal), and 20(formal), then which pairwise comparison for the difference between two groups must be significant?

the formal and informal groups

The count or frequency of participants in each category, or at each level of the categorial variable, as determined by the proportion expected in each category, is called:

the frequency expected

the degrees of freedom for the related-samples t test are:

the number of difference scores minus 1

which of the following is an assumption of the related-samples t test?

the population of difference scores is normally distributed

Which of the following tests can be reported using the z statistic?

the related-samples sign test, the Wilcoxon signed-ranks T test, the Mann-Whitney U test

the related-samples t test can be computed when:

the same participants are observed two times or in two groups

what value is placed in the denominator of the formula for estimated Cohen's d for the related-samples t test?

the standard deviation for the difference scores

Which of the following is reported for the results of a chi-square test?

the test statistic value, the p value, the degrees of freedom

To report the results of the one-way between-subjects ANOVA, which of the following is reported?

the test statistic, the p value, the degrees of freedom numerator and denominator

Homogeneity of variance refers to the assumption that:

the variance of scores in each population is equal

The null hypothesis for a chi-square test for independence is that:

two categorical variables are independent or unrelated

the one-way between-subjects ANOVA is used when different participants are assigned to _______ groups(s)

two or more

The Mann-Whitney U test is a nonparametric alternative to which hypothesis test?

two-independent-sample t test

Ordinal data do not convey distance, which is why analyzing the ___________ of ordinal data is meaningless

variance

When we measure data on a nominal or ordinal scale, we require hypothesis that use test statistics that do not analyze the _______ of the data

variance

variation attributed to mean differences among participant scores within each group is called:

within-groups variation

the source of variation that cannot be attributed to or caused by having different groups is called:

within-groups variation and error variation

a researcher reports the following result for a related-samples t test at a .05 level of significance: t(40) = 3.02, p < .05 (d = 0.20). Is this result significant?

yes, because the p value is less than 5%

Which test statistic do we use to compute the normal approximation for the Mann-Whitney U test?

z statistic

Which test statistic do we use to compute the normal approximation for the sign test

z statistic

Which test statistic do we used to compute the normal approximation for the Wilcoxon signed-ranked T test?

z statistic