## PSYC 355 Quizzes Liberty University

## PSYC 355 Analysis of Variance Liberty

- 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.