PSY 211 QR Final Exam

assumptions for a one way within subjects anova

normality independence within groups homogeneity of variance homogeneity of covariance

assumptions for a one way between subjects anova

normality random sampling independence homogeneity of variance

A key difference between a t statistic and a z statistic is that the standard error is ______ to compute a t statistic. a. removed b. replaced c. estimated d. placed in the numerator

c. estimated

Identify and explain three three limitations for evaluating a correlation coefficient.

Causality Outliers Range restriction

Identify and explain three assumptions for evaluating a correlation coefficient.

Linearity- lines look alike Homoscedasticity- assume equal variance all along the line Normality- normally distributed data was gathered

independent

Participants only used once in a sample Do not share common characteristics

A researcher conducts two studies using the one-way between-subjects ANOVA. The sum of squares between groups is smaller in Study 1 than in Study 2; the sum of squares total is the same in both studies. Using eta-squared, in which study will the effect size be larger? a. Study 1 b. Study 2 c. There is not enough information to answer this question.

b. Study 2

Which of the following post hoc tests is associated with the least power to detect an effect? a. Fisher's LSD test b. Tukey's HSD test c. Studentized Newman-Keuls d. None; each post hoc test is associated with the same power to detect an effect.

b. Tukey's HSD test

The correlation coefficient ranges from -1.0 to +1.0, with values closer to ±1.0 indicating ______. a. a less positive relationship between two factors b. a stronger relationship between two factors c. that two factors are less likely to be related d. that the correlation is due to outliers

b. a stronger relationship between two factors

when to use spearman

both factors are ranked or ordinal data

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? a. The two-independent sample t test had greater power to detect the effect. b. The two-independent sample t test was associated with fewer degrees of freedom. c. The related-samples t test had greater power to detect the effect. d. The related-samples t test was associated with more degrees of freedom.

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

Post hoc tests are computed ______. a. prior to conducting a hypothesis test b. to determine which set of degrees of freedom can be attributed to the variability between-groups c. following a significant ANOVA test to make pairwise comparisons d. to determine if groups means differ, even for tests in which the decision is to retain the null hypothesis

c. following a significant ANOVA test to make pairwise comparisons

State three advantages for selecting related samples.

o More practical o Minimizes standard errors o Increases power

residual variation

variance in y that is not related to changes in X, left over variation

The less that scores overlap between groups, the ______ the error variance. A. larger B. more valuable C. smaller D. more sizable

C. smaller

Explain why a t distribution is associated with n - 1 degrees of freedom and describe the information that is conveyed by the t statistic.

Conveyed as n-1 df because it is using sample variance

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 ______. a. repeated-measures design b. matched-samples design c. both A and B

b. matched-samples design

interaction

Source of variation associated with the variance of group means across the combination of levels of two factors

criterion variable

Y, variable with unknown values that can be predicted or estimated, given known values of the predictor variable

cell

Combination of one level from each factor as represent in a cross tabulation Each cell is a group in a research study

identify two appropriate sampling methods used to select independent samples.

Levels of between subjects factors are manipulated Different participants are randomly assigned to each group or to each level of that factor and observed one time

predictor variable

X, variable with values that are known and can be caused to predict values of another variable

Random sampling

assume that the data were obtained using a random sampling procedure

when to use phi

both factors are dichotomous (nominal data)

Which of the following indicates the strongest correlation? a. r = -0.57 b. r = +0.78 c. r = -0.90 d. r = +0.88

c. r = -0.90

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

d. both A and B

Identify each source of variation in an analysis of regression, and compute an analysis of regression and interpret the results.

regression variation residual variation

regression variation

variance in y that is related to or associated with changes in X

Calculate the degrees of freedom for the two-way between-subjects ANOVA and locate critical values in the F table.

o Df A= p-1 o Df B= q-1 o Df AxB = (p-1)(q-1)

What are the degrees of freedom for the related-samples t test? a. (nD - 1) b. (n - 1) (n - 1) c. (n - 1) + (n - 1) d. (n - 1) - (n - 1)

a. (nD - 1)

There are ______ factors in a 2 × 3 ANOVA design. a. 2 b. 3 c. 5 d. 6

a. 2

A researcher measures anxiety levels among participants in the presence and absence of a fearful stimulus. If the same participants are observed in each group, then what type of statistical design is appropriate for this study? a. a related-samples t test b. a one-way between-subjects ANOVA c. a one-way within-subjects ANOVA d. both A and C

d. both A and C

Describe the between-subjects design

different participants are observed one time in each group or at each level of a factor

Related/dependent

Patients are observed in more than one group Patients are matched based on common characteristics

main effect

Source of variation associated with mean differences across the levels of a single factor

A researcher reports that college students consume an average of 3.6 alcoholic drinks per week. What is the interval estimate in this example? A. 3.6 B. The interval estimate is not given.

B. The interval estimate is not given.

The point-biserial correlation coefficient is a measure of the direction and strength of the linear relationship between two variables, where ______. a. one is continuous and one is dichotomous b. both variables are on an ordinal scale c. one is at interval level or higher and one is ordinal d. both variables are on a nominal scale

a. one is continuous and one is dichotomous

You read about a study testing whether night shift workers sleep the recommended 8 hr per day. Assuming that the population variance of sleep (per day) is unknown, what type of t test is appropriate for this study? a. one-sample t test b. two-independent sample t test c. There is not enough information to answer this question.

a. one-sample t test

A researcher measures the extent to which the speed at which people eat (in minutes) predicts calorie intake (in kilocalories). Which factor is the predictor variable in this example? a. the speed at which people eat b. calorie intake c. minutes and kilocalories d. all of these

a. the speed at which people eat

A correlation coefficient can ______ demonstrate cause. a. always b. never c. mostly d. intermittently

b. never

Computing a one-way within-subjects ANOVA is appropriate when ______. a. different participants are assigned to each group b. the same participants are observed across groups c. the levels of one or more independent variables are manipulated d. all of these

b. the same participants are observed across groups

Using a two-way between-subjects ANOVA with Factor A (gender: male, female) and Factor B (type of employment: blue collar, white collar), a researcher found that scores for men and women significantly varied across the levels of the second factor (type of employment). In this study, the researcher found a significant ______. a. main effect of Factor A b. main effect of Factor B c. A B interaction d. post hoc test

c. A B interaction

Computing a two-independent-sample t test is appropriate when ______. a. different participants are assigned to each of two groups b. the population variance is unknown c. participants are observed one time in a given group d. all of these

d. all of these

The degrees of freedom for error is called ______. a. degrees of freedom error b. degrees of freedom denominator c. degrees of freedom within-groups d. all of these

d. all of these

between groups anova source of variation

difference between group a and group b

within groups anova source of variation

difference between group a itself

Identify the assumptions for the one-sample t test.

normality, random sampling, independence

when to use point biserial

one factors is dichotomous (nominal data) and the other factor is continuous (interval or ration data)

The source of variation that is associated with differences between groups in a study is called ______. a. between-groups variability b. within-groups variability c. between-persons variability d. error variability

a. between-groups variability

The term "within-subjects" refers to ______. a. observing the same participants in each group b. observing different participants in each group c. the type of post hoc test conducted d. the type of effect size estimate measured

a. observing the same participants in each group

independence

assume that probabilities of each measure outcome in a study are independent

normality

assume the data in the population being sampled is normally distributed

The ______ is an inferential statistic used to determine the number of standard deviations in a t distribution that a sample mean deviates from the mean value or mean difference stated in the null hypothesis. a. t distribution b. t statistic c. standard error d. degrees of freedom

b. t statistic

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? a. one-sample t test b. two-independent-sample t test c. There is not enough information to answer this question.

b. two-independent-sample t test

The correlation coefficient ranges between ______ and ______. a. 0; +1 b. -1; 0 c. -1; +1 d. -; +

c. -1; +1

Summarize the results of the one-way between-subjects ANOVA and the one-way within-subjects ANOVA in APA format.

o Report the Test statistic Degrees of freedom P value Report size for significant analysis

Calculate the degrees of freedom for a one-sample t test and locate critical values in the t table.

o Take n-1 = df o Look at t table in back of book for Alpha Df Two tailed