Stats

What is the typical level of significance for hypothesis test in behavioral research

.05

The one samples Z test is a hypothesis test use to test hypotheses

Concerning a single population with a known variance

Which of the following is an assumption for the two-independent sample t test, but not the one-sample t test?

Equal variances

The criteria for decision regarding the value stated in a null hypothesis is set by the

Level of significance

Based on the effect size conventions D equals .18 is a

Small affect size

Rejecting a true null hypothesis as a type ____ error

Type I

Which of the following summarizes a t test that was significant and associated with a large effect size?

t(12)=2.95,p<.05,d=.82

To compute a related samples t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test?

the population variance of difference scores

Based on the effect size conventions, d = 0.99 is a

large effect size

Without changing the value of error variance, the ________ the between-groups variability, the more likely we are to reject the null hypothesis

larger

Compared to the two-independent sample t test, the related samples design decreases

standard error

A researcher reports that the size of an affect in some population is D equals .88. Which of the following is an appropriate interpretation for D

Mean scores shifted . 88 standard deviationis in the population

A researcher conducts a study in which the population variance of difference scores between two groups is unknown. What type of t test is most appropriate for this study?

related samples t test

A researcher reports a significant effect with t(14) = 3.24. Compute eta-squared for this result.

n^2= 0.43 (large effect size)

A measure of the size of an effect in a population is called

effect size

The degrees of freedom for error is called

degrees of freedom error

For an analysis of variance, the term "one-way" refers to

the number of factors in the design

Two researchers (A and B) compute a one-sample t test. For both tests, the mean difference between the sample and value stated in the null hypothesis is 5, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis?

Researcher A.

A researcher reports that mean ratings of liking for some food are 0.8±2.4 (M±SD). If the null hypothesis was that the mean equals 0, then what is the effect size for this test using estimated Cohen's d?

d = 0.33; medium effect size

State the critical values for a t-test using a two-tailed test at a .05 level of significance T( 20)

+-2.086

A researcher conducts a study in which k = 5 and N = 80. What are the degrees of freedom between-groups for the one-way between-subjects ANOVA?

4

A researcher conducts a study in which the same participants are observed across each level of the independent variable. If there are only two levels of the independent variable, then what type of t test is appropriate for this study?

related samples t test

A type of related samples design in which participants are observed more than once is called a

repeated measures design

The source of variability associated with error variance in the one-way between-subjects ANOVA is called

within-groups variability

A researcher conducts a study using the one-way between-subjects ANOVA. He computes SSBG = 120 and SSE = 200. What is the effect size for this test using eta-squared?

.38

In a study with three groups and 13 participants in each group, the sum of squares for the within-groups source of variation is 18. What is the value for the mean square within-groups in this study?

0.5

Which of the following is an advantage for selecting related samples compared to selecting independent samples in behavioral research?

All of the above.

Is a one-sample t test reported differently for one-tailed and two-tailed tests?

No, the same values are reported.

Two researchers (A and B) compute a two-independent sample t test. For both tests, the mean difference between the two groups is 10, but the standard error is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis?

Researcher A.

Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean?

that the variance is equal in each population from which samples are selected

A researcher compares differences in positivity between participants in a low-, middle-, or upper-middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects AN

(2, 42)

Give the names for two commonly used measures of effect size for t tests that give you the proportion of variance explained in the DV.

eta squared and omega squared

Computing a one-way between-subjects ANOVA is appropriate when

different participants are observed one time in each of two or more groups for one factor

The degrees of freedom for the between-groups variability is called

A) degrees of freedom numerator B) degrees of freedom denominator C) degrees of freedom between-groups !!!!!D) both A and C

Following a significant one-way between-subjects ANOVA in which k > 2, what is the next appropriate step?

Conduct post hoc tests.

______ allows researchers to describe how far mean squares have shifted in the population or the percentage of variance that can be explained by a given variable

Effects size

Eta-squared is computed ______ for the one-sample, and the two-independent sample t tests.

Similarly

The test statistic for a related samples t test makes tests concerning a single sample of

difference scores

The related samples design can ________ the power to detect an effect by making the standard error ________.

increase; smaller

Which of the following is a type of related samples design in which different participants are actually observed in each group, but treated statistically as if they are the same persons in each group.

matched samples design

When reporting data in a results section, it is ____ necessary to identify the type of t test computed.

not

The related samples design can ________.

be more practical

A researcher Selects a sample of 32 participants were assigned to participate in a study with one group what is the degrees of freedom for this test

31

What is the minimum number of groups that can be observed using the one-way between-subjects ANOVA design?

2

The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05, = .12. How many participants were observed in this study?

40

"Elementary school children spent significantly more time reading the presence of a teacher than when the teacher was absent, t(7) = 2.804, p < .05 (2 = 0.46)." In this related samples t test, how many participants were observed?

8

Which measure of effect size is most commonly reported with a t test?

Cohen's d

post hoc tests are computed

Following a significant ANOVA test to make pairwise comparisons.

A researcher conducts a study but has lowe power to detect an effect which of the following is one way in which the research can increase power

Increase the sample size

The professor gives an exam in which the mean score is 78 points she gives another exam to test whether or not score is change in this example the null hypothesis is

M does not equal 78

Which of the following statements regarding the null hypothesis is true

The null hypothesis always makes statements about a population parameter

Which of the following post hoc tests is associated with the least power to detect an effect?

Tukey's HSD test

The term "between-subjects" refers to

observing different participants one time in each group

When reporting the results of a one sample Z test using APA format the _____ does not need to be reported

critical values

The T distribution is similar to the Z distribution except

all of the above

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

all of the above

Which of the following is an assumption for computing any type of independent sample t test?

all of the above

ANOVA stands for,

analysis of variance

A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male (n = 20) or female (n = 12). The mean likability ratings in each group were 4.0. If the null hypothesis is that there is no difference in likability ratings, then do likability ratings differ at a .05 level of significance?

No, this result is not significant, t(30) = 0.

Computing a two-independent sample t test is appropriate when

all of the above

For the related samples t test, assuming that all other values remain constant, then as samples size increases,

all of the above

As ______ increases the power to detect in affect increases

Sample size

Is a one-sample z test reported differently for one-tailed and two-tailed tests?

No, the same values are reported.

To compute a two-independent sample t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test?

the pooled population variance

A researcher matched 30 participants on intelligence (hence 15 pairs of participants), and then compared differences in emotional responsiveness to two experimental stimuli between each pair. For this test, what are the critical values, assuming a two-tailed test at a .05 level of significance?

±2.145

What are the degrees of freedom for the related samples t test?

(nD-1)

A researcher conducts two t-tests test one is a one tailed test with a smaller sample size at a .05 level of significance test two is a one tailed test with the larger sample size of a .05 level of significance what do you know about the critical values for each test

Test two is associated with smaller critical values

All other things being equal, as the sample size increases, what happens to the critical value for a related samples t test (or for any t test, for that matter)?

The critical value decreases.

Two researchers analyze the same data set. Researcher A uses a two-independent sample t test and decides to retain the null hypothesis. Researcher B uses a related samples t test and decides to reject the null hypothesis. Which of the following is a likely explanation for the disparity in the decisions made.

The related samples t test had greater power to detect the effect.

A researcher computes a test statistic and finds that the P value for this test is. 03 what does this result mean

There is a 3% likelihood of obtaining the test statistic the value if they null were true

A professor finds that the average SAT score among all students attended his college is 1150+ or -150. He pulled his class of 25 students and finds that the average SAT score is 1200. Suppose he computes a one sample Z test at a .05 level of significance. What is his decision

To reject the null hypothesis for an upper tailed test but to retain the null hypothesis for two tailed test

A researcher reports that the mean difference in response time to an auditory versus a visual cue is 0.83 seconds, with a pooled sample variance equal to 2.45. What is the effect size for this test using estimated Cohen's d?

d = 0.53; medium effect size

Which of the following is not one of the four steps to hypothesis testing

evaluate the plan

All other things being equal, reducing the level of significance from .05 to .01 will ________ the value of the test statistic for a related samples t test.

have no effect on

A method for testing a claim or hypothesis about a parameter and a population using data measured in a sample is called

hypothesis testing

Each of the following is an advantage for using the related samples design, except

it increases the variability measured in a study

A researcher asks a sample of brothers and sisters to rate how positive their family environment was during childhood. In this study, the differences in ratings between each brother and sister pair were compared. The type of design described here is called a

matched samples design

A researcher obtains z = 1.45 for a one-sample z test. What is the decision for this test at a .05 level of significance?

retain the null hypothesis

A researcher measures differences in recall between male and female participants following a romantic movie clip. If different participants were in each group, then what type of statistical design is appropriate for this study?

A) a two-independent sample t test B) a one-way between-subjects ANOVA C) a two-way between-subjects ANOVA !!!D) both A and B

A lowercase k is used to denote

A) the number of groups in a study B) the number of participants in a study C) the number of levels of the factor in a study !!!D) both A and C

A researcher randomly assigned 32 children to observe a short clip depicting either their favorite superhero, a parent, a teacher, or no person at all (n = 8 per group). If SSBG = 30 and SSE = 104, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA?

Retain the null hypothesis.

A researcher tests how well participants know their spouse while under hypnosis, and again without hypnosis. It was hypothesized that participant responses would be more accurate (greater number of correct responses) when under hypnosis. The mean number of correct responses was M = 5.30 under hypnosis and M = 3.40 without hypnosis in a sample of 30 participants. If the estimated standard error for difference scores was 2.52, then what is the decision at a .05 level of significance (two-tailed test)?

Retain the null hypothesis; responses were not more accurate under hypnosis.

A researcher measures deviant behavior in a sample of 12 children from abusive homes (Sample A). Another researcher measures the same behavior in a sample of 18 children from abusive homes (Sample B). Which sample is associated with larger degrees of freedom?

Sample B

Using APA format, which value is typically given in parentheses when reporting the results for a t test?

The degrees of freedom.

The power of decision-making process is

The likelihood of rejecting a false null hypothesis

The mean crying time of infants during naptime at a local preschool is 12 minutes. The school implements a new naptime routine in a sample of 25 infants and records an average crying time of 8±4.6 (M±SD) minutes. Test whether this new naptime routine reduced crying time at a .05 level of significance. A

The new naptime routine significantly reduced crying time, t(24) = -4.35, p < .05.

Given the following values u=6.0 M= 7.6 n= 36 o=6 conduct a one sample Z test at a .05 level of significance for a one tailed test upper tail critical what is the decision

To retain the null hypothesis

A researcher directly controls for the probability of a ____ but does not directly control for the probability of a______

Type one error, type two error

Computing a one-sample t test is appropriate when

all of the above

A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 grams, with a pooled sample variance equal to 256. What is the effect size for this test using estimated Cohen's d? A) d = 0.06; small effect size

d = 0.88; large effect size

Which measure of proportion of variance tends to overestimate the size of an effect in a population?

eta-squared

Which of the following is not a post hoc test for a one-way between-subjects ANOVA?

eta-squared

Using a between-subjects ANOVA design,

nk participants are each observed one time

You read about a study testing whether night shift workers sleep the recommended 8 hours per day. Assuming that the population variance of sleep (per day) is unknown, what type of t test is appropriate for this study?

one-sample t test

One difference between a repeated measures design and a matched samples design is that

only one design involves observing the same participants in each group

The denominator of the test statistic for a related samples t test

provides an estimate of the error associated with the difference scores

A researcher compares the difference in the amount of texting by students in class during the first week and last week of classes. The type of design described here is called a

repeated measures design

A researcher records differences in ratings of emotion among participants watching either a drama or a romance film. Assuming that the population variance is unknown, what type of t test is appropriate for this study?

two-independent sample t test

The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05, = .12. How many pairwise comparisons need to be made for this ANOVA result?

3

Which of the following statements is the appropriate way to read the degrees of freedom for an ANOVA with 10 participants in each of four groups?

3 and 36 degrees of freedom

A researcher assigned participants (n = 8 per group) to read vignettes describing a person engaging in either a helpful, hurtful, or neutral act. Different participants were assigned to each group and asked to rate how positively they viewed the person described in the vignette. What is the critical value for the one-way between-subjects ANOVA at a .05 level of significance?

3.47

When the variability attributed to between-groups is equal to the variability attributed to error, then the value of the test statistic for a one-way between-subjects ANOVA is

Equal to 1.

A researcher assigns 21 adolescents to rate the likability of a person described in a vignette as having one of three personality traits. An equal number of participants are assigned to each group. If Fobt = 4.08 for this study, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA?

Reject the null hypothesis.

A researcher computes the following one-way between-subjects ANOVA table. State the decision at a .05 level of significance. (Hint: Complete the table first.) Source of Variation Between groups Within groups (error) Total SS df MS F 32 4 45 122

Reject the null hypothesis.

What are the two decisions that researches can make in hypothesis testing

Retain or reject the null hypothesis

The estimated standard error in the T statistic uses the______to estimate the_____ when the population variance is unknown

Sample variance; population variance

A researcher sampled 16 couples and measured the mean difference in their marital satisfaction. Each couple was paired and the differences in their ratings (on a 7-point scale) were taken. If the mean difference in satisfaction ratings for this sample was 1.8±2.0 ( M D sD ), then what is the decision at a .05 level of significance?

Satisfaction ratings significantly differ, t(15) = 3.60.

A researcher conducts two studies. Each study was a one sample Z test both studies placed the rejection region in both tails and measured the same sample mean. The alpha level in study one was larger than the alpha level used in study 2. Which study is associated with greater power to detect an effect

Study one

The _____ is an inferential statistics used to determine the number of standard deviations in a t distribution that a sample mean deviate from the mean value or mean difference stated in the null hypothesis

T statistic