A researcher uses analysis of variance to test for mean differences among three treatments with a sample of n = 12 in each treatment. The F-ratio for this analysis would have what df values?
An ANOVA is used to evaluate the mean differences among three treatment conditions with a sample of n = 12 participants in each treatment. For this study, what is dfwithin treatments?
A researcher reports an F-ratio with df = 1, 24 for an independent-measures experiment. If all the treatments had the same number of participants, then how many individuals were in each treatment?
In an ANOVA, what is represented by the letter T?
The following table shows the results of an analysis of variance comparing three treatments. What is the value of η 2 , the percentage of variance accounted for, for these data?
An ANOVA is used to evaluate the mean differences among three treatment conditions with a sample of n = 12 participants in each treatment. For this study, what is dfbetween treatments?
In analysis of variance, what is measured by the MS values?
A researcher uses an independent-measures t test to evaluate the mean difference between two treatments and obtains t(12) = 4.00. If the researcher had used an ANOVA to evaluate the data, what F-ratio would be obtained?
On average, what value is expected for the F-ratio if the null hypothesis is true?
If an analysis of variance produces a value of F = 1.00, then all the samples have the same mean.
Posttests are only needed if H 0 is rejected in an ANOVA comparing more than two treatments.
Posttests such as Scheffé are not necessary for an analysis of variance comparing only two treatment conditions.
For an ANOVA, when the null hypothesis is true, the F-ratio is balanced so that the numerator and the denominator are both measuring the same sources of variance.
For an independent-measures ANOVA comparing four treatment conditions, dfbetween = 3.
A research report presents the results of an independent-measures ANOVA as follows: F (3, 28) = 5.36, p < .01. If all the samples were the same size, then each sample had n = 7 participants.
PSYC 355 Correlation Liberty University
If the following seven scores are ranked from smallest (#1) to largest, what rank should be assigned to a score of X = 6? Scores: 1, 1, 3, 6, 6, 6, 9
What correlation is obtained when the Pearson correlation is computed for data that have been converted to ranks?
A researcher measures IQ and weight for a group of college students. What kind of correlation is likely to be obtained for these two variables?
A set of n = 5 pairs of X and Y values has SSX = 16, SS Y = 4 and SP = 2. For these data, what is the Pearson correlation?
A researcher obtains a Pearson correlation of r = 0.60 for a sample of n = 6 pairs of X and Y scores. If the researcher tests the significance of the correlation, what value will be obtained for the t statistic?
For a group of graduating college seniors, a researcher records each student’s rank in his/her high school graduating class and the student’s rank in the college graduating class. Which correlation should be used to measure the relationship between these two variables?
Three main characteristics of a correlation coefficient include all of the following except:
A researcher records the age and price for a group of used Hondas. What kind of correlation is likely to be obtained for these two variables?
What is indicated by a positive value for a correlation?
Suppose that there is a correlation of r = 0.41 between the amount of time that each student reports studying for an exam and the student’s grade on the exam. This correlation would mean that there is a tendency for people who study more to get better grades.
The value obtained for the sum of products, SP, determines the sign (+/–) for the Pearson correlation.
A researcher obtains SSX = 20, SSY = 5, and SP = 7 for a set of n = 25 pairs of scores. The Pearson correlation for these scores is r = 7/10 = 0.70.
If people are classified by age (over 30/under 30) and by political affiliation (Democrat/Republican), then the point-biserial correlation would be the proper technique to measure the relationship between the two variables.
The sign of the correlation (+/–) is generally meaningless for the point-biserial correlation and the phi-coefficient.
For a two-tailed hypothesis test evaluating the significance of a correlation, the null hypothesis states that the sample correlation is zero.
PSYC 355 p-Value Review
Is the following p value significant or not significant? Use the critical value of a = .05. Select the correct answer to the question.p = .10
Is the following p value significant or not significant? Use the critical value of a = .05. Select the correct answer to the question.p = .01
Is the following p value significant or not significant? Use the critical value of a = .05. Select the correct answer to the question.p = .46
Is the following p value significant or not significant? Use the critical value of a = .05. Select the correct answer to the question.p = .027
Is the following p value significant or not significant? Use the critical value of a = .05. Select the correct answer to the question.p = .27
Is the following p value significant or not significant? Use the critical value of a = .01. Select the correct answer to the question.p = .0015
Is the following p value significant or not significant? Use the critical value of a = .01. Select the correct answer to the question.p = .10
Is the following p value significant or not significant? Use the critical value of a = .01. Select the correct answer to the question.p = .04
Is the following p value significant or not significant? Use the critical value of a = .01. Select the correct answer to the question.p = .007
If SPSS gives a significance value of p = .000, how would you report this in your APA-style results?
An independent-measures study uses n = 15 participants in each group to compare two treatment conditions. What is the df value for the t statistic for this study?
One sample has M = 18 and a second sample has M = 14. If the pooled variance for the two samples is 16, what is the value of Cohen’s d?
Which combination of factors is most likely to produce a significant value for an independent-measures t statistic?
The data from an independent-measures research study produce a sample mean difference of 4 points and a pooled variance of 18. If there are n = 4 scores in each sample, what is the estimated standard error for the sample mean difference?
One sample has n = 10 scores and a variance of s2 = 20, and a second sample has n = 15
An independent-measures research study uses two samples, each with n = 10 participants. If the data produce a t statistic of t = 2.095, which of the following is the correct decision for a two-tailed hypothesis test?
Assuming a 5-point difference between the two sample means, which set of sample characteristics is most likely to produce a significant value for the independent- measures t statistic?
What is assumed by the homogeneity of variance assumption?
For the independent-measures t statistic, what is the effect of increasing the difference between sample means?
For an independent-measures t statistic, the estimated standard error measures how much difference is reasonable to expect between the sample means for two samples selected from the same population.
If an independent-measures t statistic has df = 20, then a total of 18 individuals participated in the research study.
For an independent-measures t statistic, you typically must compute the pooled variance before calculating the estimated standard error.
An independent-measures study has M1 = 49 and M2 = 45 with an estimated standard error of 4. For this study, Cohen’s d = 4/4 = 1.00.
If both samples have the same number of scores (n), then the independent-measures t statistic will have df = 2n – 2.
For a hypothesis test with the independent-measures t statistic, the null hypothesis states that the two population means are the same and the homogeneity assumption states that the two population variances are the same.
PSYC 355 t-Test for Two Related Samples
Which of the following is the correct null hypothesis for a repeated-measures t test?
A researcher plans to conduct a research study comparing two treatment conditions with a total of 20 participants. Which of the following designs would produce 20 scores in each treatment?
The following data were obtained from a repeated-measures research study. What is the value of MD for these data?
A researcher is using a repeated-measures study to evaluate the difference between two treatments. If the difference between the treatments is consistent from one participant to another, then the data should produce .
For which of the following situations would a repeated-measures research design be appropriate?
A repeated-measures study using a sample of n = 20 participants would produce a t statistic with df = .
A researcher obtains t = 2.25 for a repeated-measures study using a sample of n = 10 participants. Based on this t value, what is the correct decision for a two-tailed test?
Which of the following possibilities is a serious concern with a repeated-measures study?
A repeated-measures study comparing two treatments with n = 4 participants produces MD = 2 and SS = 75 for the difference scores. What is the estimated standard error for the sample mean difference?
If all participants in a repeated-measures study show roughly the same 10-point difference between treatments, then the data are likely to produce a significant value for the t statistic.
Repeated-measures designs are particularly well-suited to research studies examining
For a repeated-measures study, as the sample mean difference increases, the likelihood of rejecting the null hypothesis also increases.
A repeated-measures research study comparing two treatments with a set of 10 scores in each treatment will produce a t statistic with df = 18.
For a repeated-measures study, if other factors are held constant, then an increase in the sample size will increase the likelihood of finding a significant treatment effect.
A repeated-measures test usually is more likely to detect a real treatment effect than an independent-measures test because the repeated-measures design typically has a smaller variance and a smaller estimated standard error.
PSYC 355 Two-Factor Analysis of Variance
Two-Factor Analysis of Variance
The repeated-measures ANOVA is a two-stage process. Which of the following accurately describes what happens during this process?
A repeated-measures ANOVA has SSwithin treatments = 26 and SSbetween subjects = 12. For this analysis, what is the value for SSerror?
A two-factor study with two levels of factor A and three levels of factor B uses a separate group of n = 5 participants in each treatment condition. How many participants are needed for the entire study?
In a repeated-measures ANOVA, the variability within treatments is divided into two components. What are they?
A two-factor research study is used to evaluate the effectiveness of a new blood-pressure medication. In this two-factor study, Factor A is medication versus no medication and factor B is male versus female. The medicine is expected to reduce blood pressure for both males and females, but it is expected to have a much greater effect for males. What pattern of results should be obtained if the medication works as predicted?
The results of a two-factor analysis of variance produce df = 1, 30 for the F-ratio for factor A, and df = 2, 30 for the F-ratio for the AxB interaction. Based on this information, how many levels of factor B were compared in the study?
A researcher reports an F-ratio with df = 2, 40 from a repeated-measures ANOVA. How many treatment conditions were compared in this experiment?
How many separate groups of participants would be needed for an independent-measures, two-factor study with 3 levels of factor A and 4 levels of factor B?
The results from a two-factor analysis of variance show a significant main effect for factor A and a significant main effect for factor B. Based on this information, what can you conclude about the interaction?
A two-factor analysis of variance produces an F-ratio for factor A that has df = 3, 36. This analysis is comparing three different levels of factor A.
For an independent-measures two-factor analysis of variance, all F-ratios use the same denominator.
A repeated-measures study uses a sample of n = 8 participants to evaluate the meandifferences between two treatment conditions. The analysis of variance for this study will have dferror = 7.
Because the repeated-measures ANOVA removes variance caused by individual differences, it usually is more likely to detect a treatment effect than the independent-measures ANOVA is. Obtaining a significant interaction means that both factors A and B have significant main effects.
A repeated-measures study uses a sample of n = 10 participants to evaluate the mean differences among three treatment conditions. For this study, dfbetween subjects = 18.