Research Methods and Statistics Prepjet Exam #2,3,4,5,7

The time-series group design is most similar to which of the following single-subject designs? A. AB B. ABAB C. multiple-baseline across behaviors D. multiple-baseline across subjects

A. AB The time-series design is a type of within-subjects design that's essentially a group version of the single-subject AB design. It involves measuring the dependent variable at regular intervals multiple times before and after the independent variable is administered.

__________ validity refers to the extent to which research results are generalizable to other people, settings, and times. A. External B. Ecological C. Exogeneous D. Endogenous

A. External External validity refers to the generalizability of research results and includes population validity (generalizability to other people in the population the sample was drawn from), ecological validity (generalizability to other settings or environments), and temporal validity (generalizability to other times).

Which of the following is the appropriate bivariate correlation coefficient to use when the scores to be correlated are both reported as ranks? A. Spearman B. Pearson C. biserial D. point biserial

A. Spearman The full-name of the Spearman correlation coefficient is the Spearman rank-order correlation coefficient. As its name suggests, it's used to correlate scores on two variables that are reported as ranks.

When designing a research study, you would use the double-blind technique to reduce which of the following? A. experimenter expectancy B. carryover effects C. pretest sensitization D. false consensus effect

A. experimenter expectancy When using the single-blind technique, subjects do not know which groups they are in (e.g., drug or placebo); when using the double-blind technique, subjects and experimenters do not know what groups subjects are in. An advantage of the double-blind technique is that it reduces experimenter expectancy, which is also known as experimenter bias and refers to the effects of the experimenter's knowledge about the purpose of the study on the study's outcomes. Neither the single-blind nor the double-blind technique are useful for controlling carryover effects or pretest sensitization which are threats to a study's external and internal validity, respectively. The false consensus effect is not relevant to internal or external validity and is the tendency to overestimate the extent to which other people share our opinions, values, and beliefs

A scatterplot is constructed from the scores obtained by a sample of employees on a newly developed selection test (X) and a measure of job performance (Y). The scatterplot indicates that the variability of Y scores is about the same for all scores on X. Which of the following terms describes this situation? A. homoscedasticity B. heteroscedasticity C. unrestricted range D. restricted range

A. homoscedasticity The terms homoscedasticity and heteroscedasticity are used to describe the relationship between two variables in terms of the amount of variability in one variable for different values of the other variable. Homoscedasticity occurs when the variability of scores on one variable is about the same at different values of the other variable; heteroscedasticity occurs when the variability of scores on one variable differs at different values of the other variable. Homoscedasticity is one of the conditions that tends to increase the correlation coefficient. Also, when data are homoscedastic, the use of a regression equation to predict people's scores on Y from their scores on X will produce the same accuracy of prediction for all scores on X.

Increasing alpha from .01 to .05: A. increases statistical power and the probability of making a Type I error. B. increases statistical power and the probability of making a Type II error. C. decreases statistical power and the probability of making a Type I error. D. decreases statistical power and the probability of making a Type II error.

A. increases statistical power and the probability of making a Type I error. Increasing alpha from .01 to .05 increases the likelihood that the null hypothesis will be rejected. Consequently, if the null hypothesis is true, this increases the probability that a true null hypothesis will be rejected - i.e., it increases the likelihood that a Type I error will occur. Or, if the null hypothesis is false, this increases the probability that a false null hypothesis will be rejected - i.e., it increases statistical power.

A research study has adequate __________ validity when it provides accurate information about the effects of an independent variable on a dependent variable. A. internal B. external C. convergent D. divergent

A. internal A research study has adequate internal validity when its results allow a researcher to draw accurate conclusions about the effects of an independent variable on a dependent variable. It has adequate external validity when the results can be generalized to other people and conditions.

A researcher conducts a study to compare four different diet programs on weight loss for individuals who have either high, moderate, or low self-esteem. The statistical analysis of the data he collects indicates that there are statistically significant main and interaction effects. This means that: A. interpreting the main effects without considering the interaction can lead to erroneous conclusions. B. interpreting the interaction is unnecessary because main effects are always most important. C. the interaction must be interpreted with caution because the main effects are significant. D. there must have been a calculation error since it's impossible to have both significant main and interaction effects.

A. interpreting the main effects without considering the interaction can lead to erroneous conclusions. When there's a statistically significant interaction between independent variables, this means that the effects of one independent variable are different for different levels of another independent variable. For example, assume that, overall, diet program #1 results in the greatest amount of weight loss. In other words, there's a main effect of diet program. However, there's also a significant interaction between diet program and self-esteem, with the benefits of diet program #1 being true only for people with high and moderate self-esteem: For people with low self-esteem, diet program #2 produced the greatest amount of weight loss. In other words, the effects of the diet programs are different for people with different levels of self-esteem. In this situation, drawing a conclusion about the effectiveness of the four diet programs on the basis of the main effect of diet program would lead to an erroneous conclusion.

In a positively skewed distribution of scores, the __________ has the lowest value and the __________ has the highest value. A. mode; mean B. mean; mode C. median; mean D. mean; median

A. mode; mean Skewed distributions are asymmetrical with most scores "piled up" in one side of the distribution and a few scores in the tail on the opposite side: In a negatively skewed distribution, the few scores are in the negative tail (the low end of the distribution); in a positively skewed distribution, the few scores are in the positive tail (the high end of the distribution) - i.e., the "tail with the few scores tells the tale." In both types of skewed distributions, the mean, median, and mode do not equal the same value: Instead, the mean is in the tail with the few scores, the median is in the middle, and the mode is in the tail containing most of the scores. Consequently, in a positively skewed distribution, the mean has the highest value, the median has the middle value, and the mode has the lowest value.

In a positively skewed distribution of scores, the __________ is the lowest score and the __________ is the highest score. A. mode; mean B. mean; mode C. median; mean D. mean; median

A. mode; mean Skewed distributions are asymmetrical with most scores "piled up" in one tail of the distribution and a few scores in the other tail: In a positively skewed distribution, the few scores are in the positive tail (the high end of the distribution); in a negatively skewed distribution, the few scores are in the negative tail (the low end of the distribution) - i.e., the "tail tells the tale." In both distributions, the mean, median, and mode do not equal the same value: Instead, the mean is in the tail with the few scores, the median is in the middle, and the mode is in the tail containing most of the scores. Consequently, in a positively skewed distribution, the mean is the highest score, the median is the middle score, and the mode is the lowest score. Conversely, in a negatively skewed distribution, the mean is the lowest score, the median is the middle score, and the mode is the highest score.

A researcher wants to evaluate the effects of virtual reality exposure for treating the storm, height, and spider phobias of a 34-year-old woman. The best single-subject research design for evaluating this treatment is which of the following? A. multiple baseline B. reversal C. discrete trials D. time series

A. multiple baseline Of the three single-subject designs listed in the answers (multiple baseline, reversal, and discrete trials), the multiple baseline design would be the most appropriate because it would allow the researcher to determine if the treatment is effective for any of the woman's phobias by sequentially applying the treatment to them. In addition, the multiple baseline design doesn't require a treatment to be withdrawn once it's been applied to a behavior. Consequently, if the treatment has a beneficial effect on any of the woman's phobias, the researcher would not have to withdraw the treatment during the course of the study just for the sake of assessing its effects.

An advertising agency has been hired by a dog food company to re-design the labels for its products. The agency prepares seven different labels for canned dog food and, to determine which label customers prefer, has a sample of 300 dog owners choose the label they like the most. Which of the following is the appropriate statistical test to use to determine if there's a significant difference in the number of dog owners who chose each label? A. single-sample chi-square test B. multiple-sample chi-square test C. one-way ANOVA D. factorial ANOVA

A. single-sample chi-square test The first and second steps in identifying the appropriate statistical test are identifying the study's independent and dependent variables and the scale of measurement of the dependent variable. However, this study has only one variable and, in this situation, it's just necessary to identify that variable's scale of measurement: The variable is type of label and it's measured on a nominal scale. The chi-square test is used to analyze nominal data and, when there's only one variable, the single-sample chi-square test is the appropriate test. Note that the single-sample chi-square test is also known as the one-sample chi-square test and the chi-square goodness-of-fit test.

The analysis of covariance (ANCOVA) is used to: A. statistically remove the effects of an extraneous variable on the dependent variable. B. measure the effects of an extraneous variable on the dependent variable by treating it as an independent variable. C. simultaneously assess the effects of the independent variable on two or more dependent variables. D. simultaneously assess the effects of two or more independent variables on a single dependent variable.

A. statistically remove the effects of an extraneous variable on the dependent variable. The ANCOVA is used to statistically remove the effects of an extraneous variable from scores on the dependent variable so that it's easier to detect the effects of the independent variable on the dependent variable. When using the ANCOVA, the extraneous variable is the "covariate."

To compare the effectiveness of two brief treatments for social anxiety disorder, you obtain a sample of individuals who have received this diagnosis, determine the severity of each subject's social anxiety, match the subjects in pairs based on the severity of their symptoms, and randomly assign one member of each pair to one of the treatments and other member to the other treatment. To compare the scores subjects in the two groups receive on a measure of symptom severity after they receive treatment, you will use which of the following? A. t-test for correlated samples B. t-test for uncorrelated samples C. two-way ANOVA D. single-sample chi-square test

A. t-test for correlated samples The first steps in identifying the appropriate statistical test are to identify the independent and dependent variables and the scale of measurement of the dependent variable. This study's independent variable is type of treatment and the dependent variable is score on a measure of severity of anxiety following treatment. More specifically, the dependent variable is score on a measure of symptom severity and, for the exam, you can assume that scores represent an interval or ratio scale. This means that a statistical test will be used to compare the mean scores obtained by two groups. The t-test and two-way ANOVA are both used to compare mean scores but, because there are only two means, the t-test is the appropriate test. To determine which t-test to use, you determine how the means were obtained: In this study, they were obtained from related groups (from groups that consist of subjects who were matched in terms of initial symptom severity). The t-test for correlated samples is the appropriate test when two means are obtained from the same group or from two groups that are related in some way.

When using the A-B-A-B single-subject design: A. there are two no-treatment phases and two treatment phases with the same treatment being applied in both treatment phases. B. there are two no-treatment phases and two treatment phases with a different treatment being applied in each treatment phase. C. there are four treatment phases with two different treatments each being applied twice. D. there are four treatment phases with four different treatments each being applied once.

A. there are two no-treatment phases and two treatment phases with the same treatment being applied in both treatment phases. n the context of single-subject designs, the letter "A" always designates a no-treatment (baseline) phase and the other letters designate a treatment phase. When the other letter is the same - as in the A-B-A-B design - this indicates that the same treatment (B) is applied twice. In contrast, when the other letters are different - as in the A-B-A-C design - this indicates that two different treatments (B and C) are each applied once.

When measuring the relationship between two variables, a restriction in range of scores on the variables will most likely produce a correlation coefficient that: A. underestimates the actual relationship between the variables. B. overestimates the actual relationship between the variables. C. either under- or overestimates the actual relationship between the variables. D. neither under- nor overestimates the actual relationship between the variables.

A. underestimates the actual relationship between the variables. Regression-07 Answer A is correct. To determine the true relationship between variables, scores on both variables must be unrestricted in terms of range. When the range is restricted (e.g., when only low scorers are included in sample), the resulting correlation coefficient will underestimate their actual relationship.

An achievement test has been given to 1,000 middle-school students. The scores obtained by the students are normally distributed and have a mean of 150 and standard deviation of 15. Given this information, you can conclude that ____% of students obtained scores above 165. A. 32 B. 16 C. 5 D. 2.5

B. 16 In a normal distribution, 68% of scores fall between the scores that are one standard deviation below and above the mean, and the remaining 32% of scores are divided between the positive and negative tails of the distribution: 16% of scores are below the score that is one standard deviation below the mean and 16% are above the score that is one standard deviation above the mean. In the distribution described in the question, the score of 165 is one standard deviation above the mean, which means that 16% of scores fall above this score.

A test has a mean of 60 and standard deviation of 5, and test scores are normally distributed. Based on this information, you can conclude that about 95% of scores fall between scores of: A. 55 and 65. B. 50 and 70. C. 45 and 75. D. 40 and 80.

B. 50 and 70. In a normal distribution about 95% of scores fall between the scores that are plus and minus two standard deviations from the mean. This test has a mean of 60 and standard deviation of 5, so about 95% of scores fall between 60 plus and minus 10 (5 x 2), which is between 50 and 70.

When evaluating the effectiveness of an intervention to eliminate the head banging of a child with autism spectrum disorder, a researcher would be least likely to use which single-subject research design? A. AB B. ABAB C. multiple baseline D. counterbalanced

B. ABAB Of the three single-subject designs listed in answers A, B, and C, the ABAB design would be least desirable in the situation described in the question. Although the AB and multiple baseline designs (answers A and C) have disadvantages, those disadvantages are not unique to the situation described in this question. However, a disadvantage of the ABAB design applies to studies investigating the effects of a treatment to eliminate a self-injurious behavior: Removing a successful treatment during the second baseline (A) phase just to see if the treatment caused the elimination of the self-injurious behavior during the initial treatment (B) phase would be unethical. [Counterbalanced (answer D) can be eliminated because it is a type of group design.]

The __________ design is a type of counterbalanced design. A. Solomon four-group B. Latin square C. cross-sectional D. multiple-baseline

B. Latin square Counterbalancing is used to control order effects that may occur when a within-subjects design is used - i.e., when subjects in each group will receive or participate in all levels of the independent variable. The Latin square is a type of counterbalanced design that ensures that the different levels of the independent variable are assigned to the groups of subjects so that each level appears an equal number of times in each ordinal position.

Which of the following is a type of counterbalanced design? A. Solomon four-group B. Latin square C. factorial D. multiple-baseline

B. Latin square Counterbalancing is used to control order effects that may occur when a within-subjects design is used - i.e., when subjects in each group will receive or participate in all levels of the independent variable. The Latin square is a type of counterbalanced design that ensures that the different levels of the independent variable are assigned to the groups of subjects so that each level appears an equal number of times in each ordinal position.

To determine the degree of association between age in years and reaction time in seconds, you would use which of the following correlation coefficients? A. Spearman rho B. Pearson r C. contingency coefficient D. biserial coefficient

B. Pearson r Because age in years and reaction time in seconds both represent a ratio scale of measurement, the Pearson r would be the appropriate correlation coefficient.

When a predictor included in a multiple regression equation has a negative beta weight, this means that: A. The predictor has a negative correlation with the other predictors. B. The predictor has a negative correlation with the criterion. C. The predictor has a statistically significant relationship with the criterion. D. The predictor does not have a statistically significant relationship with the criterion.

B. The predictor has a negative correlation with the criterion. Beta weights are standardized regression coefficients, and a predictor's beta weight indicates the strength of the relationship between the predictor and the criterion. When a predictor's beta weight is positive, this means there's a positive relationship between the predictor and criterion (i.e., as scores on the predictor increase, scores on the criterion increase). Conversely, when the beta weight is negative, this means there's a negative relationship between the predictor and criterion (i.e., as scores on the predictor increase, scores on the criterion decrease).

You obtain the data you need from a sample of licensed psychologists to calculate a correlation coefficient for their EPPP score and yearly salary five years after taking the exam. If you square the correlation coefficient, you will obtain a(n) _______________, which indicates the amount of variability in yearly salary that's accounted for by EPPP score. A. coefficient of concordance B. coefficient of determination C. kappa coefficient D. eta coefficient

B. coefficient of determination Squaring a correlation coefficient produces a coefficient of determination, which is a measure of shared variability - or, put another way, a measure of the amount of variability in one variable that is accounted for by variability in another variable.

An advantage of conducting a single one-way ANOVA rather than separate t-tests when a study includes one independent variable with three or more levels is that the ANOVA: A. provides information on both main and interaction effects. B. controls the experimentwise error rate. C. reduces the effects of measurement error. D. controls the effects of an extraneous variable.

B. controls the experimentwise error rate. The experimentwise error rate is the probability of making a Type I error when multiple statistical comparisons are made within a single research study. If an independent variable has three or more levels, several t-tests would have to be conducted because the t-test compares only two means at a time, and this would increase the experimentwise error rate. When using the one-way ANOVA, all possible comparisons between means are made in a way that maintains the experimentwise error rate at the alpha level set by the researcher.

Which of the following scales of measurement allows you to conclude that the difference between the scores of 50 and 51 on a test is equal to the difference between the scores of 90 and 91 on the same test? A. ordinal, interval, and ratio B. interval and ratio C. interval only D. ratio only

B. interval and ratio Interval and ratio scales both have the property of equal intervals between adjacent points on the scale. Equal intervals allow you to draw the conclusion that the one-point difference between the scores of 50 and 51 on a test is equal to the one-point difference between the scores of 90 and 91 on the same test.

In a negatively skewed distribution of scores, the __________ is the lowest score and the __________ is the highest score. A. mode; mean B. mean; mode C. median; mean D. mean; median

B. mean; mode Skewed distributions are asymmetrical with most scores "piled up" in one tail of the distribution and a few scores in the other tail: In a negatively skewed distribution, the few scores are in the negative tail (the low end of the distribution); in a positively skewed distribution, the few scores are in the positive tail (the high end of the distribution) - i.e., the "tail tells the tale." Consequently, in a negatively skewed distribution, the mean is the lowest score, the median is the middle score, and the mode is the highest score.

A study conducted by Kaczynski, Lindahl, Malik, and Laurenceau (2006) confirmed their hypothesis that the relationship between marital conflict and child adjustment was due to the impact of marital conflict on parenting style which, in turn, impacted child adjustment. In this situation, parenting style is a(n) ________ variable. A. moderator B. mediator C. extraneous D. independent

B. mediator Mediator variables are also known as intervening variables and explain the relationship between two other variables. Kaczynski et al. found that the relationship between marital conflict and child adjustment was explained (mediated) by parenting style. In others, they found that parenting style was a mediating variable.

According to the stress buffering hypothesis, stressful life events are less likely to lead to depression or other negative outcomes for people who feel they have adequate social support than for people who feel they don't have adequate social support. In this situation, social support is a(n) _________ variable. A. mediator B. moderator C. extraneous D. independent

B. moderator A moderator variable affects the direction and/or strength of the relationship between two variables. In the situation described in this question, perceived social support moderates (affects) the likelihood that stressful life events will lead to depression and other negative outcomes.

You would use which of the following statistical tests to compare the number of adults living in a rural, urban, or suburban community who have received a diagnosis of a bipolar disorder, depressive disorder, or anxiety disorder? A. single-sample chi-square test B. multiple-sample chi-square test C. one-way ANOVA D. factorial ANOVA

B. multiple-sample chi-square test The first and second steps in identifying the appropriate statistical test are identifying the study's independent and dependent variables and the scale of measurement of the dependent variable. This study has two variables (diagnosis and community type); however, it's a descriptive study rather than an experimental study, so it's difficult to identify one of the variables as the independent variable and the other as the dependent variable. In this situation, you identify the scale of measurement of the data to be analyzed. The data are the frequency (number) of individuals in each category - e.g., the number of people who live in an urban area and have received a diagnosis of a bipolar disorder. In other words, the scale of measurement is nominal: Subjects will not receive a score but will belong to a category. The chi-square test is used to analyze nominal data and, when there's more than one variable, the multiple-sample chi-square test is the appropriate test. Note that the multiple-sample chi-square test is also known as the chi-square test for contingency tables.

Which of the following is considered the most effective way to control extraneous variables? A. random selection of subjects from the population B. random assignment of subjects to the different treatment groups C. statistically removing their effects from the independent variable D. statistically removing their effects from the dependent variable

B. random assignment of subjects to the different treatment groups An extraneous variable is a variable that has not been designated as an independent or dependent variable in a research study but affects the study's results. A researcher always wants to control extraneous variables so that the effects of an independent variable on the dependent variable can be detected. Methods used to control extraneous variables include random assignment of subjects to treatment groups, treating the extraneous variable as an independent variable, and statistically removing the effects of the extraneous variable. Of these, random assignment of subjects is considered the most effective method because it helps ensure that groups are initially equivalent in terms of all extraneous variables, even those that are unknown.

A psychologist is planning a research study to evaluate the effects of a two-hour online lecture on statistics for improving the statistics knowledge of 35 psychologists who have just started studying for the EPPP. All participants will (1) take a pre-test consisting of 50 multiple-choice statistics questions on Monday, (2) attend the online lecture on Wednesday evening, and (3) take a post-test consisting of 50 multiple-choice statistics questions that are equivalent to the pre-test questions on Friday. To analyze the data she obtains in her study, the researcher will use which of the following? A. t-test for a single sample B. t-test for correlated samples C. two-way ANOVA D. single-sample chi-square test

B. t-test for correlated samples The first steps in identifying the appropriate statistical test are to identify the independent and dependent variables and the scale of measurement of the dependent variable. This study's independent variable is the lecture on statistics and the dependent variable is statistics test score. The dependent variable is measured on a ratio scale, which means that the statistical test will be used to compare the mean scores obtained by the psychologists on the pre- and post-tests. The t-test and ANOVA are both used to compare mean scores, but because there are only two means, the t-test is the appropriate test. To determine which t-test to use, you determine how the means will be obtained: In this study they will be obtained from a single group of subjects, and the t-test for correlated samples is used when two means are obtained from the same group or from two groups that are related in some way.

Your one-way ANOVA produces a statistically significant F-ratio. In this situation, you would consider conducting a post-hoc test if: A. the independent variable has only two levels. B. the independent variable has three or more levels. C. there is more than one dependent variable. D. the interaction between independent variables is also statistically significant.

B. the independent variable has three or more levels. A one-way ANOVA is used when a study has one independent variable and one dependent variable (which is why answers C and D can be eliminated). When it produces a statistically significant F-ratio, this indicates that at least one group mean is significantly different from another group mean. If there are only two groups (two levels of the independent variable), a post-hoc test is not necessary because the significant F-ratio indicates that the means of those two groups are significantly different. However, when there are three or more groups (three or more levels of the independent variable), a post-hoc test is useful for determining which group means are significantly different. (Comparing the magnitude of the means obtained by the groups indicates which group means differ, but a post-hoc test is needed to determine which differences are statistically significant.)

The scores obtained by 35 students on a math exam and a physics exam are converted to ranks. To determine the degree of association between the two sets of ranks, the appropriate correlation coefficient is which of the following? A. biserial B. point biserial C. Spearman D. Pearson

C. Spearman Knowing that "Spearman" refers to the Spearman rank-order correlation coefficient would have helped you identify the correct answer to this question. As its name suggests, it's used to determine the correlation between rank-ordered data.

All of the single-subject designs share which of the following characteristics? A. The independent variable is not withdrawn during the course of the study once it's been applied. B. The independent variable is applied to two or more baselines. C. The dependent variable is measured multiple times during each phase. D. The dependent variable is measured before and after the independent variable is applied.

C. The dependent variable is measured multiple times during each phase. All of the single-subject designs involve measuring the dependent variable multiple times at regular intervals during each baseline phase and each treatment phase. The other answers apply to some, but not all, of the single-subject designs.

When two variables are measured on an interval or ratio scale and their relationship is nonlinear, you would use which of the following correlation coefficients to assess their degree of association? A. Spearman rho B. contingency C. eta D. biserial

C. eta An assumption that must be met for most bivariate correlation coefficients is that there's a linear relationship between the two variables that will be correlated. An exception is eta, which is used when both variables are measured on a continuous (interval or ratio) scale and the relationship between the variables is nonlinear.

The use of participant observation to study a cultural group is most associated with which of the following approaches to qualitative research? A. grounded theory B. thematic analysis C. ethnography D. phenomenology

C. ethnography Participant observation is the primary method of data collection for ethnographic research and involves joining a cultural group and participating in its usual activities.

A researcher would use the split-plot ANOVA to analyze the data she collected in her research study when: A. she wants to statistically remove the effects of an extraneous variable on the dependent variable. B. she wants to assess the effects of one independent variable on three dependent variables that are all measured on an interval or ratio scale. C. her study included one between-subjects independent variable and one within-subjects independent variable. D. her study included an extraneous variable that was treated like an independent variable.

C. her study included one between-subjects independent variable and one within-subjects independent variable. Knowing that the split-plot ANOVA is also known as the mixed ANOVA may have helped you identify the correct answer to this question: It is used when data are collected from a study that used a mixed design - i.e., that had at least one between-subjects variable and one within-subjects variable.

A researcher would use the split-plot ANOVA to analyze the data she collects in her research study when: A. she wants to statistically remove the effects of an extraneous variable on the dependent variable. B. she wants to assess the effects of one independent variable on three dependent variables that are all measured on an interval or ratio scale. C. her study included one between-subjects independent variable and one within-subjects independent variable. D. her study included one or more extraneous variables that were treated like independent variables.

C. her study included one between-subjects independent variable and one within-subjects independent variable. Knowing that the split-plot ANOVA is also known as the mixed ANOVA may have helped you identify the correct answer to this question: It's used when data are collected from a study that used a mixed design - i.e., that had at least one between-subjects independent variable and one within-subjects independent variable.

Structural equation modeling (SEM) is used to test models of the relationships among: A. observed variables only. B. latent variables only. C. observed and latent variables. D. observed and manifest variables.

C. observed and latent variables. An advantage of SEM is that it allows researchers to test models of the relationships among observed and latent variables. Observed variables are also known as manifest variables and indicators and can be directly measured. Latent variables are also known as factors and constructs and cannot be measured directly but are inferred from observed variables.

To determine the correlation between college graduate (yes or no) and yearly income in dollars, you would use which of the following correlation coefficients? A. phi coefficient B. Pearson r C. point biserial coefficient D. Spearman rho

C. point biserial coefficient The point biserial correlation coefficient is used when one variable is a true dichotomy (e.g., college graduate or nongraduate) and the other variable is continuous (e.g. yearly income in dollars).

The standard error of the mean increases in size as the: A. population standard deviation and sample size decrease. B. population standard deviation and sample size increase. C. population standard deviation increases and sample size decreases. D. population standard deviation decreases and sample size increases.

C. population standard deviation increases and sample size decreases. The standard error of the mean is the standard deviation of the sampling distribution of the mean and is used to determine how well a sample mean estimates a population mean. It's calculated by dividing the population standard deviation by the square root of the sample size, and it increases as the population standard deviation increases and the sample size decreases, and vice versa.

The Solomon four-group design is used to control which of the following threats to a study's internal validity? A. history B. statistical regression C. pretest sensitization D. differential selection

C. pretest sensitization Pretest sensitization is also known as testing and threatens a study's internal validity whenever taking a pretest systematically affects subjects' performance on the posttest. When using the Solomon four-group design, the effects of taking a pretest can be assessed which helps determine if an apparent effect of the independent variable on the dependent variable is actually due to the independent variable rather than the pretest.

A researcher has made a Type II error when she: A. rejects a false null hypothesis. B. rejects a true null hypothesis. C. retains a false null hypothesis. D. retains a true null hypothesis.

C. retains a false null hypothesis. There are two decision errors a researcher can make when interpreting the results of a research study: A Type I error occurs when a researcher rejects a true null hypothesis - i.e., when he/she erroneously concludes that the independent variable had an effect on the dependent variable. A Type II error occurs when a researcher retains a false null hypothesis - i.e., when he/she erroneously concludes that the independent variable did not have an effect on the dependent variable.

A company's current selection procedure for computer programmers consists of seven predictors that are used to predict the job performance score that a job applicant will receive six months after being hired. The owner of the company wants to reduce the costs and time required to make selection decisions. Which of the following would be most useful for determining the fewest number of predictors needed to make accurate predictions about applicants' job performance scores? A. linear regression analysis B. discriminant function analysis C. stepwise multiple regression D. factor analysis

C. stepwise multiple regression Multiple regression is used to predict a person's score on a single criterion (e.g., job performance measure) using two or more predictors. Stepwise multiple regression is a type of multiple regression that's used to identify the fewest number of predictors needed to make an accurate prediction.

The main characteristic that distinguishes true experimental research from quasi-experimental research is that, when conducting a true experimental research study: A. the results of the study can be analyzed using a parametric statistical test. B. the results of the study can be analyzed using a parametric or nonparametric statistical test. C. subjects are randomly assigned to treatment groups. D. subjects are randomly selected from the population.

C. subjects are randomly assigned to treatment groups. True experimental research is distinguished from quasi-experimental research by two main characteristics. The researcher can (a) manipulate the independent variable(s) - i.e., decide which groups receive different levels of the variable(s) and (b) randomly assign subjects to the different groups.

To compare an obtained sample mean to a known population mean, you would use which of the following? A. ANCOVA B. one-way ANOVA C. t-test for a single sample D. single sample chi-square test

C. t-test for a single sample t-test is always used to compare two means and the appropriate t-test depends on how the means were obtained. When an obtained sample mean will be compared to a known population mean, the t-test for a single sample is the appropriate t-test. In this situation, the sample is the treatment group and the population is being used as the control (no treatment) group.

When using Bayes' theorem: A. the likelihood function is derived from a synthesis of the prior and posterior. B. the prior is derived from a synthesis of the posterior and likelihood function. C. the posterior is derived from a synthesis of the prior and likelihood function. D. the prevailing is derived from a synthesis of the prior, likelihood function, and posterior.

C. the posterior is derived from a synthesis of the prior and likelihood function. Bayes' theorem combines the prior probability distribution for the target parameter and the probability distribution for the parameter derived from current data (the likelihood function) to obtain a posterior (updated) probability distribution for the parameter. [There is no "prevailing" (answer D) in Bayes' theorem.]

When conducting a one-way ANOVA, an F-ratio is calculated by dividing the mean square between (MSB) by the mean square within (MSW). The mean square between provides an estimate of variability in dependent variable scores due to: A. treatment effects only. B. error only. C. treatment effects plus error. D. treatment effects minus error.

C. treatment effects plus error. MSB is a measure of variability due to a combination of treatment effects plus error, while MSW is a measure of variability due to error only. When MSB is divided by MSW, this produces the F-ratio which provides an estimate of treatment effects.

Dr. Oz conducts a study to compare the effects of three treatments (drug, relaxation, and drug plus relaxation) on the systolic blood pressure of patients who have secondary hypertension as the result of three different conditions (tobacco use, chronic alcohol use, or obesity). To analyze the main and interaction effects of treatment and condition on systolic blood pressure, Dr. Oz will use which of the following statistical tests? A. chi-square test for multiple samples B. t-test for independent samples C. two-way ANOVA D. MANOVA

C. two-way ANOVA The first two things to do when choosing an inferential statistical test are to identify (1) the independent and dependent variables and (2) the scale of measurement of the dependent variable. This study has two independent variables - treatment and condition - and one dependent variable - systolic blood pressure. You may have had trouble with this question because you were uncertain about the scale of measurement of systolic blood pressure. However, a general rule is that most physical measurements (including systolic blood pressure) represent an interval or ratio scale, which means that the appropriate statistical test will be a t-test or analysis of variance. To choose between the t-test, the two-way ANOVA, and the MANOVA, you have to consider how many independent and dependent variables there are. There are two independent variables, which eliminates the t-test because it's used when there's only one independent variable; and there is one dependent variable, which eliminates the MANOVA because it's used when there are two or more dependent variables. That leaves the two-way ANOVA, which is the correct answer. It's used when a study includes two independent variables and one dependent variable that's measured on an interval or ratio scale.

To compare the effects of three SAT review programs, a researcher randomly assigns a sample of male and female high school students who have high, average, or low test anxiety to one of the three programs. Following completion of the programs, he assesses each student's level of anxiety and performance on a mock SAT exam. This study has ___ independent variables and ___ dependent variable(s). A. 2; 1 B. 3; 1 C. 2; 2 D. 3; 2

D. 3; 2 If you're having trouble distinguishing between a study's independent and dependent variables, remember that independent variables are believed to have an effect on the dependent (outcome) variables and that, for questions like this one, anything that varies will be either an independent or dependent variable. Converting the information given in the description of the study to the following question might be helpful: "What are the effects of the [independent variable(s)] on the [dependent variable(s)]?" For this study, the question is, "What are the effects of the three review programs, initial level of test anxiety, and gender on mock SAT exam scores and level of anxiety after participation in the programs?" In other words, this study has three independent variables (program, anxiety level, and gender) and two dependent variables (SAT score and anxiety level).

A psychologist conducts a study to evaluate the effects of three different work shifts (day, swing, and graveyard) on the average number of errors, absences, and accidents of assembly line workers during a six-month period. To minimize the probability of making a Type I error, the psychologist will use which of the following to analyze the data she collects? A. one-way ANOVA B. three-way ANOVA C. ANCOVA D. MANOVA

D. MANOVA The MANOVA (multivariate analysis of variance) is used when a study includes one or more independent variables and two or more dependent variables that are each measured on an interval or ratio scale. An advantage of conducting a single MANOVA rather than separate ANOVAs for each dependent variable is that doing so reduces the probability of making a Type I error - i.e., it reduces the experimentwise error rate. The study described in this question has one independent variable (work shift) and three dependent variables that are all measured on a ratio scale (number of errors, absences, and accidents). Therefore, the MANOVA can be used to analyze the data collected in this study.

The central limit theorem predicts that, regardless of the shape of the population distribution of scores, a sampling distribution of means increasingly approaches the shape of: A. the population distribution as the number of samples increases. B. the population distribution as the sample size increases. C. a normal distribution as the number of samples increases. D. a normal distribution as the sample size increases.

D. a normal distribution as the sample size increases. According to the central limit theorem, the shape of the sampling distribution of means increasingly approaches a normal shape as the sample size increases, regardless of the shape of the population distribution of scores. (The central limit theorem assumes an infinite number of equal-sized samples, and its prediction about the shape of the sampling distribution is based on the size of the samples.)

The reliable change index (RCI) is useful for determining if a change in a client's scores on an outcome measure administered before and after the client receives treatment is: A. valid. B. statistically significant. C. attributable to sampling error. D. attributable to measurement error.

D. attributable to measurement error. As its name suggests, the reliable change index is used to determine if a difference in pre- and post-treatment scores on an outcome measure is reliable - i.e., if it is due to real improvement or deterioration in a person's clinical condition or to measurement error. The RCI is also used in conjunction with the outcome measure's cutoff score to determine if a change in scores is clinically significant.

An advantage of the single-subject ABAB design is that it enables a researcher to: A. compare the effects of a treatment on two different behaviors. B. compare the effects of two different treatments by administering them at two different times. C. be more certain that the observed effects of the treatment can be generalized to different conditions. D. be more certain that the treatment is responsible for any observed change in the subject's behavior.

D. be more certain that the treatment is responsible for any observed change in the subject's behavior. When using the single-subject ABAB design, the study includes two baseline (A) phases and two treatment (B) phases, and the study begins with a baseline (no treatment) phase that's followed by application of the treatment, a second baseline phase in which the treatment is withdrawn, and a second treatment phase in which the same treatment is applied. If the target behavior changes in the predicted way during both treatment phases and the second baseline phase, a researcher can be fairly confident that a change in the behavior was due to the treatment.

You have developed a battery of tests to determine which of five vocational training programs is most appropriate for unemployed young adults who dropped out of high school. Which of the following multivariate techniques will be useful in this situation? A. multiple regression B. multivariate analysis of variance C. canonical correlation D. discriminant function analysis

D. discriminant function analysis Discriminant function analysis is also known as discriminant analysis and is the appropriate technique when two or more predictors will be used to categorize people into one of two or more criterion groups - e.g., to use a person's scores on two or more tests to determine which of five vocational training programs is the best one for him or her.

A distinguishing characteristic of community-based preparatory research (CBPR) is that community members who take part in CBPR act as: A. research subjects who help identify the goals of the research. B. advocates who support the work of the research team. C. subject matter experts who act as consultants. D. equal research partners who participate in all phases of the research.

D. equal research partners who participate in all phases of the research. CBPR differs from traditional community-based research by its inclusion of community members as equal research partners with other members of the research team during all phases of the research. Even if community members adopt other roles during the course of the research, their primary role is that of a research partner.

In the context of research design, external validity refers to: A. consistency. B. accuracy. C. causality. D. generalizability.

D. generalizability. A research study has good external validity when its results can be generalized to other people, settings, and conditions.

Dr. Osprey conducted a study to evaluate the effects of an anti-drug program on attitudes toward drug use for middle school students from low-income families. Subjects were 662 7th and 8th graders attending an inner-city school. Attitudes toward drugs were assessed in the second week of September, the five-hour anti-drug program was administered in five one-hour sessions during the second week of October, and attitudes toward drugs were then re-assessed in the second week of November. Results indicated that the program significantly increased negative attitudes toward drug use. The biggest threat to the internal validity of this study is which of the following? A. statistical regression B. selection C. reactivity D. history

D. history History threatens a study's internal validity whenever an external event that occurs during the course of the study has a systematic effect on subjects' scores or status on the dependent variable(s). Given that this study includes only one group of subjects and takes place over a two-month period of time, the biggest threat to its internal validity is history. For example, many of the students may have changed their attitudes not because of the anti-drug program but because they were exposed to information about drug use during the two months in a biology or health class or a TV or billboard ad campaign.

A psychologist designs a study to compare the effects of mindfulness-based cognitive therapy (MBCT) and mindfulness-based stress reduction (MBSR) on the anxiety symptoms of clinic patients who have just received a diagnosis of social anxiety disorder. The study will involve randomly assigning patients to one of the two treatments and measuring their level of social anxiety during the first treatment session and one week, one month, and three months following the end of treatment. The psychologist is using which of the following research designs? A. counterbalanced B. between subjects C. multiple baseline D. mixed

D. mixed To identify the correct answer to this question, you have to recognize that this study has two independent variables: type of treatment and time. (Time is an independent variable when the dependent variable is measured on multiple occasions during the course of the study.) Type of treatment is a between-subjects variable because each subject will participate in only one of the two interventions (MBCT or MBSR), while time is a within-subjects variable because each subject's level of anxiety will be measured four times. When a study includes at least one between-subjects variable and one within-subjects variable, the study has a mixed design.

A researcher conducts a study to determine if there are gender differences in acceptance as a graduate student into the six largest departments at a university. To analyze the data she collects in this study, the researcher will use which of the following? A. one-way ANOVA B. two-way ANOVA C. single-sample chi-square test D. multiple-sample chi-square test

D. multiple-sample chi-square test The first and second steps in identifying the appropriate statistical test are identifying the study's independent and dependent variables and the scale of measurement of the dependent variable. This study has two variables - gender and department - and gender can be viewed as the independent variable and department as the dependent variable. The dependent variable - department - is a nominal variable. The chi-square test is the appropriate test for analyzing nominal data and, when a study has two or more variables, the multiple-sample chi-square test is used. Keep in mind that, for the chi-square test, you count the total number of variables regardless of whether they're independent or dependent variables: The multiple-sample chi-square test is used when the study has two or more variables, and the single-sample chi-square test is used when a study is a descriptive study and has only one variable.

The standard error of the mean decreases in magnitude as the: A. population standard deviation and sample size decrease. B. population standard deviation and sample size increase. C. population standard deviation increases and sample size decreases. D. population standard deviation decreases and sample size increases.

D. population standard deviation decreases and sample size increases. The standard error of the mean is the standard deviation of the sampling distribution of means and is used to determine how well a sample mean estimates a population mean. It's calculated by dividing the population standard deviation by the square root of the sample size, and it decreases in magnitude as the population standard deviation decreases and the sample size increases, and vice versa.

The Solomon four-group design is used to evaluate the effects of _________ on a study's internal and external validity. A. history B. differential selection C. attrition D. pretesting

D. pretesting Administering a pretest as a part of a research study can threaten the internal and external validity of the study. The Solomon four-group design allows a researcher to determine if the apparent effects of the independent variable on the dependent variable are due to the independent variable or due, at least in part, to exposure to the pretest (i.e., to determine if the study has internal validity). It also allows the researcher to determine if the effects of the independent variable generalize to situations in which a pretest is not administered (i.e., to determine if the study has external validity).

To help ensure that differential selection doesn't threaten the internal validity of a research study, an investigator will: A. include more than one group in the research study. B. use the single- or double-blind technique. C. randomly select participants from the population. D. randomly assign participants to different levels of the independent variable.

D. randomly assign participants to different levels of the independent variable. It should have been easy to identify the correct answer to this question as long as you remembered that the name of this threat is misleading since it is the result of the way subjects are assigned to treatment groups rather than how they are selected from the population. It threatens a study's internal validity when subjects in different groups differ in an important way at the beginning of the study, and the best way to control it is to randomly assign subjects to the treatment groups.

Parametric statistical tests are more "powerful" than nonparametric tests which means that, when using a parametric test, you're more likely to: A. retain a true null hypothesis. B. reject a true null hypothesis. C. retain a false null hypothesis. D. reject a false null hypothesis.

D. reject a false null hypothesis. In the context of inferential statistics, power is also known as statistical power and refers to the ability to detect (and reject) a false null hypothesis. Several factors affect power including the type of statistical test that's used: Parametric tests (e.g., t-test and analysis of variance) are more powerful than nonparametric tests (e.g., chi-square test) because of the type of data that are analyzed by parametric tests and because of the assumptions that must be met to use them.

When designing and conducting a research study, you can increase statistical power by doing which of the following? A. reducing the size of alpha B. decreasing the effect size C. randomly selecting subjects from the population D. using a parametric test when it's appropriate to do so

D. using a parametric test when it's appropriate to do so Increasing the size of alpha, increasing the effect size (the magnitude of the effects of the independent variable), and using a parametric test when it's appropriate to do so are methods for increasing statistical power, which is the ability to reject a false null hypothesis. Randomly selecting subjects from the population increases a study's external validity but does not affect statistical power.

You would use the multivariate analysis of variance (MANOVA) to analyze the data you obtain in a research study when: A. you want to control the effects of an extraneous variable by statistically removing its effects on the dependent variable. B. you want to measure the main and interaction effects of an extraneous variable on the dependent variable. C. your study includes at least one between-subjects variable and one within-subjects variable. D. your study includes two or more dependent variables that are measured on an interval or ratio scale.

D. your study includes two or more dependent variables that are measured on an interval or ratio scale. The MANOVA is used when a study includes one or more independent variables and two or more dependent variables that are each measured on an interval or ratio scale.