Question 1

The probability of a Type II error increases when

Accepted Answer

A)  lower significance levels are used. 
B)  larger sample sizes are selected. 
C)  a stronger relationship in the population is assumed. 
D)  statistical power is calculated on a post hoc bsis. 
A)  lower significance levels are used. 
B)  larger sample sizes are selected. 
C)  a stronger relationship in the population is assumed. 
D)  statistical power is calculated on a post hoc bsis. A

Question 2

Ignoring statistical power can result in

Accepted Answer

A)  conducting a study with a sample size that is too small. 
B)  wasting resources by selecting a sample that is much smaller than needed. 
C)  overlooking the probability of committing a Type I error. 
D)  nonparametric outcomes. 
A)  conducting a study with a sample size that is too small. 
B)  wasting resources by selecting a sample that is much smaller than needed. 
C)  overlooking the probability of committing a Type I error. 
D)  nonparametric outcomes. A

Question 3

An experiment is conducted to test the effectiveness of a social work intervention.The experimental group improves more than does the control group,but the results are not statistically significant.This means that

Accepted Answer

A)  the intervention was not effective. 
B)  the intervention was effective, but not at a significant level. 
C)  we cannot rule out sampling error in inferring about the effectiveness of the intervention. 
D)  the sample size was too large. 
A)  the intervention was not effective. 
B)  the intervention was effective, but not at a significant level. 
C)  we cannot rule out sampling error in inferring about the effectiveness of the intervention. 
D)  the sample size was too large. C

Question 4

Describe the controversy regarding statistical significance testing with population data.

Accepted Answer

The controversy regarding statistical si

Question 5

If two correlated variables each have a bivariate correlation of .25 with a third variable,then the multiple correlation of the three variables combined will be .50.

Accepted Answer

A) True 
 B)False

Question 6

Two different studies assessing the effectiveness of two different types of social work intervention in preventing psychiatric hospitalization are conducted in two different regions by two different teams of researchers.One study,conducted in a rural area,finds that the mean number of days hospitalized for 10 treated clients is 60,as compared to a mean of 80 for 10 untreated clients.But this difference is not statistically significant.The other study,conducted in an urban area,finds a statistically significant p<05 difference in which 48 percent of 1,000 treated clients received some hospitalization,as compared to 52 percent of 1,000 untreated clients.What can and cannot be inferred about the comparative effectiveness of the two interventions? Explain.Can we infer that one intervention appears to be more effective than the other? Why or why not?

Accepted Answer

When comparing the effectiveness of two

Question 7

Chi-square should be used to test the significance of relationships between the ratio level variables.

Accepted Answer

A) True 
 B)False

Question 8

Statistical power increases when

Accepted Answer

A)  larger sample sizes are selected. 
B)  lower significance levels are used. 
C)  a weaker relationship in the population is assumed. 
D)  it is done on a post hoc basis. 
A)  larger sample sizes are selected. 
B)  lower significance levels are used. 
C)  a weaker relationship in the population is assumed. 
D)  it is done on a post hoc basis.

Question 9

Nonparametric tests are intended for use when some assumptions of parametric tests cannot be met.

Accepted Answer

A) True 
 B)False

Question 10

Multiple regression analysis shows the overall correlation between each of a set of independent variables and an interval- or ratio-level dependent variable.

Accepted Answer

A) True 
 B)False

Question 11

Parametric tests assume

Accepted Answer

A)  interval- or ratio-level measurement of all variables. 
B)  a normal sampling distribution of variables with interval- or ratio-level data. 
C)  nonprobability sampling. 
D)  nominal level measurement of all variables. 
A)  interval- or ratio-level measurement of all variables. 
B)  a normal sampling distribution of variables with interval- or ratio-level data. 
C)  nonprobability sampling. 
D)  nominal level measurement of all variables.

Question 12

Meta-analysis procedures can be used to calculate the statistical significance of results aggregated across various studies that by themselves did not have statistically significant results.

Accepted Answer

A) True 
 B)False

Question 13

If your statistical power is .60,then your probability of a Type II error is .40.

Accepted Answer

A) True 
 B)False

Question 14

A statistical power analysis tells us:

Accepted Answer

A) How large our effect size is. 
B)  The probability of avoiding a Type II error assuming our hypothesis is true. 
C)  The probability of committing a Type I error. 
D)  How much substantive significance our findings have. 
A) How large our effect size is. 
B)  The probability of avoiding a Type II error assuming our hypothesis is true. 
C)  The probability of committing a Type I error. 
D)  How much substantive significance our findings have.

Question 15

Identify four different tests of statistical significance and the conditions under which each would be used.

Accepted Answer

1. T-test: The t-test is used to determi

Question 16

Which of the following statements is/are true about a multivariate statistical analyses in which variable A has a .20 correlation with variable C,and variable B has a .20 correlation with variable C?

Accepted Answer

A) Variables A and B together must accounor 40 percent of the variation in variable C. 
B)  Variables A and B together must accounor 4 percent of the variation in variable C. 
C)  If variables A and B are correlated with each other, then variables A and B together will accounor less than 40 percent of the variation in variable C. 
D)  If variables A and B are correlated with each other, then variables A and B together will accounor more than 40 percent of the variation in variable C. 
A) Variables A and B together must accounor 40 percent of the variation in variable C. 
B)  Variables A and B together must accounor 4 percent of the variation in variable C. 
C)  If variables A and B are correlated with each other, then variables A and B together will accounor less than 40 percent of the variation in variable C. 
D)  If variables A and B are correlated with each other, then variables A and B together will accounor more than 40 percent of the variation in variable C.

Question 17

Which of the following statistics can be used to determine whether there is a statistically significant difference between three treatment groups in number of days hospitalized?

Accepted Answer

A)  t-test 
B)  chi-square 
C)  analysis of variance 
D)  Pearson's product-moment r 
A)  t-test 
B)  chi-square 
C)  analysis of variance 
D)  Pearson's product-moment r

Question 18

A rigorous and trustworthy meta-analysis worthy of guiding evidence-based practice decisions should:

Accepted Answer

A)  include published studies, only. 
B)  be transparent about potential conflicts of interest. 
C)  calculate one mean effect size based on all included studies, regardless of their methodological strengths or weaknesses. 
D)  avoid calculating the overall level of statistical significance. 
A)  include published studies, only. 
B)  be transparent about potential conflicts of interest. 
C)  calculate one mean effect size based on all included studies, regardless of their methodological strengths or weaknesses. 
D)  avoid calculating the overall level of statistical significance.

Question 19

Which statistical significance test should be used in a study of whether the mean number of days worked by case-managed clients is greater than the mean worked by non-case-managed clients?

Accepted Answer

A)  t-test. 
B)  chi-square. 
C)  Pearson's product-moment r. 
D)  Fisher's exact test. 
A)  t-test. 
B)  chi-square. 
C)  Pearson's product-moment r. 
D)  Fisher's exact test.

Question 20

A researcher conducts 20 tests of statistical significance,one for each independent variable,wita.05 significance level.Only one test yields a probability value that is not greater than .05.What can we infer about the latter test?

Accepted Answer

A)  The probability of committing a Type I error in rejecting the null hypothesis is .05. 
B)  It is a statistically significant predictor of the dependent variable. 
C)  Because so many tests were conducted, the probability of committing a Type I error is greater than .05. 
D)  Because so many tests were conducted, the probability of committing a Type I error is much smaller than .001. 
A)  The probability of committing a Type I error in rejecting the null hypothesis is .05. 
B)  It is a statistically significant predictor of the dependent variable. 
C)  Because so many tests were conducted, the probability of committing a Type I error is greater than .05. 
D)  Because so many tests were conducted, the probability of committing a Type I error is much smaller than .001.

Exam 23: Inferential Data Analysis

The probability of a Type II error increases when

Ignoring statistical power can result in

An experiment is conducted to test the effectiveness of a social work intervention.The experimental group improves more than does the control group,but the results are not statistically significant.This means that

Describe the controversy regarding statistical significance testing with population data.

If two correlated variables each have a bivariate correlation of .25 with a third variable,then the multiple correlation of the three variables combined will be .50.

Chi-square should be used to test the significance of relationships between the ratio level variables.

Statistical power increases when

Nonparametric tests are intended for use when some assumptions of parametric tests cannot be met.

Multiple regression analysis shows the overall correlation between each of a set of independent variables and an interval- or ratio-level dependent variable.

Parametric tests assume

Meta-analysis procedures can be used to calculate the statistical significance of results aggregated across various studies that by themselves did not have statistically significant results.

If your statistical power is .60,then your probability of a Type II error is .40.

A statistical power analysis tells us:

Identify four different tests of statistical significance and the conditions under which each would be used.

Which of the following statements is/are true about a multivariate statistical analyses in which variable A has a .20 correlation with variable C,and variable B has a .20 correlation with variable C?

Which of the following statistics can be used to determine whether there is a statistically significant difference between three treatment groups in number of days hospitalized?

A rigorous and trustworthy meta-analysis worthy of guiding evidence-based practice decisions should:

Which statistical significance test should be used in a study of whether the mean number of days worked by case-managed clients is greater than the mean worked by non-case-managed clients?

A researcher conducts 20 tests of statistical significance,one for each independent variable,wita.05 significance level.Only one test yields a probability value that is not greater than .05.What can we infer about the latter test?

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Philosophy and Theory in Social Work Research

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Constructing Measurement Instruments

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Quasi-Experimental Designs

Single-Case Evaluation Designs

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Sampling

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Analyzing Existing Data: Quantitative and Qualitative Methods

Qualitative Research: General Principles

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Qualitative Data Analysis

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