Exam 3 mcq

• 13 * In an evaluation of an intervention that seeks to increase self-esteem scores, the experimental group mean is 40, and the control group mean is 22. The pooled standard deviation is 6. Therefore, Cohen’s d equals: 3.0
• 13* If a correlation coefficient equals .30, then: 9 percent of the dependent variable variation is explained.
• 13* If Study A reports a Cohen’s d of .60, and Study B reports a correlation coefficient of .60, then: study B’s effect size is stronger than Study A’s effect size
• 13* Which of the following statements is/are true about meta-analyses? their findings could be skewed by the problem of publication bias (or the file drawereffect).
• 13* Interpreting the strength and practical implications of effect sizes based on correlation coefficients is: None of these.
• 13* According to approximate guidelines for interpreting the strength of effect sizes, a Cohen’s d of .55 is considered to be: Moderate
• 13* According to approximate guidelines for interpreting the strength of effect sizes, a Pearson’s r of .30 is considered to be: Moderate
• 13* A statistically significant finding: None of these
• 13* If statistical power is .80, then the probability of a Type II error is: 0.20
• 13* We would increase statistical power if we: increase the sample size
• 13* Trivial relationships: Can be statistically significant with very large sample sizes.
• 13* Which of the following statements is true about correlation statistics? they can be calculated with variables at any level of measurement.
• 13* Which of the following is true about correlation statistics? Two variables can be correlated if increases in one variable are accompanied by decreases in the other variable with most cases, but not necessarily with all cases
• 13* Which of the following is true about correlation statistics? negative correlation of -.30 is stronger than a positive correlation of +.25
• 13* Which of the following is true about correlation statistics? weak correlation in one study might be more desirable than a strong correlation in another study if the two studies differ with regard to what variables are being correlated.
• 13* Which of the following is true about effect-size statistics? The odds ratio is an effect-size statistic used in logistic regression with dichotomous
• 13* All strong and statistically significant relationships are considered to be substantively: false
• 13* A correlation of -.40 indicates that 40 percent of the variation in the dependent variable is explained: false
• 13* Effect-size statistics enable us to compare the effects of different interventions acrossstudies using different types of outcome measure: true
• 13* A Cohen’s d of .30 and a correlation coefficient of .30 both signify the same degree of relationship strength: false
• 13* Differences in effect sizes automatically indicate which intervention is more effective: false
• 13* Substantive significance refers to how meaningful a finding is to clients, significant: True
• 13* Clinical significance can refer to the meaningfulness and practical value of the benefits of an intervention for each individual recipient of the evaluated intervention: true
• 13* Each of the three statistical approaches that have been proposed for measuring clinical significance is considered by some to be controversial: true
• 13* Some studies can have sample sizes that are so small that researchers have little likelihood of being able to refute sampling error even with effect sizes that most would agree are substantively or clinically significant: true
• 13* The statistical power of a study is its probability of correctly rejecting a null hypothesis that is false: true
• 13* The probability of committing a Type II error is one minus statistical power: true
• 14* It is appropriate to use the t-Test when: the independent variable is nominal and dichotomous and the dependent variable is at the interval or ratio level of measurement.
• 14* It is appropriate to use the t-Test when: Comparing the means of two groups
• 14* It is appropriate to use the independent-samples t-Test when: We want to compare the means of two independent groups.
• 14* It is appropriate to use the paired-samples t-Test when: we want to compare the means of pairs of individuals who have been matched because they are similar to each other
• 14* It is appropriate to use the one-sample t-Test when: we want to compare a sample statistic to a population statistic.
• 14* The t–Test formula involves calculating a t–score by: Dividing the difference between two means by the standard error of the difference between means.
• 14* When using an independent-samples t-Test, which of the following is considered when calculating the degrees of freedom? All of these.
• 14* In a pilot study, Dana wants to test the significance of the improvement in mean scores from pretest to posttest. Dana should use: he paired-samples t-Test
• 14* Chris wants to test the significance of the difference in the number of treatment sessions attended by clients who have no connection to one another and who have been randomly assigned to either Group A and Group B. Chris should use: the independent-samples t-Test.
• 14* (back end) Randy conducts two paired-sample t-Tests and finds a p value of .04 for Intervention A’s improvement and a p value of .06 for Intervention B’s improvement. Randy then conducts an independent-samples t-Test of the posttest scores and finds a p value of .55. Which of the following statements is an appropriateconclusion from Randy’s findings? we cannot conclude that either intervention is effective in improving self-esteem scores
• 14* Which of the following statements is correct regarding the t distribution? It will be flatter and more spread out with a small sample than with a large sample.
• 14* How many degrees of freedom are there in a t-test for a study in which there are 50 clients in the experimental group and 40 clients in the control group? 88
• 14* Suppose a study is done in which the experimental and control groups both get pretests and posttests. Which of the following is the best statistical procedure? Conduct an independent-samples t-test that compares the changes scores in the two groups.