Biostats #1-123
11. The degrees of freedom for a chi-square test for independence test are [k are categories, n are sample size] A) k - 1 B) n - 1 C) (k1 - 1)(k2 - 1) D) (k - 1)(n - 1)
C) (k1 - 1)(k2 - 1)
1. Which of the following is an example of a nonparametric test? A) a z test B) a paired t-test C) chi-square test D) confidence interval estimation
C) chi-square test
118. To standardize the beta coefficients, we first, A) analyze the significance of each data point B) analyze the residual variation C) convert the original data to standardized z scores D) compute the standard error of estimate
C) convert the original data to standardized z scores
16. When assumptions regarding expected cell counts are not met, an alternative test to the chi-square test is: A) McNemar's test. B) The Goodness of Fit test. C) The Sign test. D) Fisher's Exact test.
D) Fisher's Exact test.
89. A researcher reports the following equation for a best-fitting straight line to a set of data points: Y^hat = 0.48X + 12.03. Which value is the slope? A) Y ^ hat B) 0.48 C) 12.03 D) The slope is not given in this equation.
B) 0.48
75 A correlation coefficient can ______ demonstrate cause. A) always B) never C) mostly D) intermittently
B) never
74. Outliers can change the _____ of a correlation. A) direction B) strength C) sign (+, -) D) all of the above
D) all of the above
5. The degrees of freedom for a chi-square goodness-of-fit test are [k=# categories, n=sample size] A) k - 1 B) n - 1 C) (k1 - 1)(k2 - 1) D) (k - 1)(n - 1)
A) k - 1
88. A researcher reports the following equation for a best-fitting straight line to a set of data points: .Y^hat = -1.01X + 3.24 Which value is the y-intercept? A) Y ^ hat B) X C) ñ1.01 D) 3.24
D) 3.24
112. Multiple regression is a statistical method that includes ____ predictor variable(s) in the equation of the regression line. A) zero B) one C) two D) two or more
D) two or more
61. The denominator of the correlation coefficient measures the extent to which two variables A) vary together B) vary independently C) covary D) both A and C
B) vary independently
Which test should be used if the expected values in any cell are fewer than 5? A. McNemar's Test B. Chi-Square GOF test C. Chi-Square Test of Independence D. Fisher's Exact Test
D. Fisher's Exact Test
41. When the variability attributed to between-groups is equal to the variability attributed to error, then the value of the test statistic for a one-way between-subjects ANOVA is, A) Equal to 0. B) Equal to 1. C) Significant at any sample size. D) Undefined in that the test statistic cannot be computed in this case.
B) Equal to 1.
56. The correlation coefficient ranges from -1.0 to +1.0, with values closer to ±1.0 indicating A) a more 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
21. The source of variability associated with error variance in the one-way between-subjects ANOVA is called A) between-groups variability B) within-groups variability C) degrees of freedom D) both A and B
B) within-groups variability
7. A researcher conducts a chi-square goodness-of-fit test in which k = 5 (k=# categories). What is the critical value for this test at a .05 level of significance? A) 4 B) 5 C) 9.49 D) 11.07
C) 9.49
42. Following a significant one-way between-subjects ANOVA in which k > 2, what is the next appropriate step? A) Summarize the data; no further tests are required. B) Interpret the data; no further tests are required. C) Conduct post hoc tests. D) both A and B
C) Conduct post hoc tests.
85. Linear regression describes the extent to which _______ predicts ________. A) X; Y B) the predictor variable; the outcome variable C) the known variable; the to-be-predicted variable D) all of the above
D) all of the above
55. The correlation coefficient is used to measure the ________ and ________ of the linear relationship between two factors. A) date; time B) mean; variance C) significance; effect size D) strength; direction
D) strength; direction
Calculate SSxy, slope = 3 and SSx = 20 A. 60 B. 0.15 C. 6.67 D. 54 E. 3.56
A. 60
Spearman Correlation testing: A. Can be used to test relationship between years of undergraduate education and a bimodal class distribution of test scores B. Can be used to test ordinal data C. Uses d.f. = n D. All of the above E. Only B and C
D. All of the above
6. As a general rule, the larger the degrees of freedom for a chi-square test, A) the smaller the critical value will be B) the larger the critical value will be C) the smaller the level of significance will be D) the larger the level of significance will be
B) the larger the critical value will be
78. A researcher measures the correlation in rankings for a sample of restaurants and consumers' rankings of their favorite restaurants. If ΣD2 = 96 and n = 12, then what is the value of the correlation coefficient? A) 0.07 B) 0.34 C) 0.66 D) 0.94
C) 0.66
52. The null hypothesis for the Kruskal-Wallis test is A) the difference in ranks for the groups do not differ B) the median values for the groups do not differ C) the sum of the ranks in each group do not differ D) the sum of the ranks in each group do differ
C) the sum of the ranks in each group do not differ
86. Which of the following is used to determine the linear equation that "best fits" a set of data points? A) correlational analysis B) analysis of variance C) analysis of regression D) method of least squares
D) method of least squares
65. Suppose a correlation is computed in each of two samples. If the value of SSXY is the same in each sample, and √SSXSSY is larger in Sample 1, then in which sample will the value of the correlation coefficient be larger? A) Sample 1 B) Sample 2 C) None; the correlation coefficient will be the same in both samples. D) There is not enough information to answer this question.
B) Sample 2
27. 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 the above
D) all of the above
29. A researcher conducts a study in which k = 5 and N = 80. What are the degrees of freedom between-groups for the one-way between-subjects ANOVA? A) 4 B) 5 C) 75 D) 395
A) 4
If Chocolate tastes good by itself, and Vinegar also tastes good by itself, BUT Chocolate and Vinegar taste awful together, is this an example of an interaction? A. YES B. NO
A. YES
108. What is the computation for the standard error of estimate? A) the square root of the mean square regression B) the square root of the mean square residual C) the mean square regression, squared D) the mean square residual, squared
B) the square root of the mean square residual
120. In addition to evaluating the significance of a multiple regression equation, we also should consider: A) the significance of the residual variability B) the complexity of the correlation coefficient C) the relative contribution of each factor D) the significance of each individual data point
C) the relative contribution of each factor
4. A chi-square goodness-of-fit test shows that the frequencies observed fit well with those that were expected. Hence, the decision was to A) reject the null hypothesis B) retain the null hypothesis C) no decision was made D) accept the null hypothesis
B) retain the null hypothesis
69. The normality assumption states that the population of X and Y scores form a bivariate ("two variable") normal distribution, such that A) the population of X and Y scores are normally distributed B) for each X score, the distribution of Y scores is normally distributed C) for each Y score, the distribution of X scores is normally distributed D) all of the above
D) all of the above
71. Which of the following is a limitation for interpreting a correlation? A) Correlations do not demonstrate cause-and-effect. B) Outliers can change the direction and/or strength of the correlation. C) Conclusions should not be drawn beyond the range of scores measured. D) all of the above
D) all of the above
94. A researcher reports the following regression equation for two variables, X and Y: Y-hat = 5.10X -1.50 . If X = 2.30, then what is the value of Y-hat? A) 10.23 B) 11.73 C) 13.23
A) 10.23
114. One key advantage for including multiple predictor variables in the equation of a regression line is that it allows you to A) detect mean differences between groups for each criterion variable B) detect the extent to which two or more predictor variables interact C) show cause-and-effect because many predictor variables are added D) all of the above
B) detect the extent to which two or more predictor variables interact
73. A researcher observes a correlation of values from 2 to 10 points and draws conclusions about the full range of values in the population from 0 to 21 points. Which limitation for correctly interpreting a correlation coefficient did the researcher violate? A) reverse causality B) restriction of range C) a confound variable D) homoscedasticity
B) restriction of range
81. Which of the following would not be reported for a correlation? A) the sample size B) the coefficient of determination C) the critical values for each test D) the strength and direction of the correlation
B) the coefficient of determination C) the critical values for each test
31. Which of the following is an assumption for computing a one-way between-subjects ANOVA? A) The population being sampled from is normally distributed. B) Participants were selected to participate using a random procedure. C) One observation has no effect on the likelihood of another observation. D) all of the above
D) all of the above
A study is done to examine the effects of steroids on rat muscle growth Which of these could be a potential confounding variable? 1. Age 2. Diet 3. Illness 4. All of the above
4. All of the above
105. A researcher computes the following analysis of regression table. Based on the data given, what is the decision for this test at a .05 level of significance? (Note: Complete the table first.) Source of Variation SS df MS F Regression 1 28 Residual Total 118 19 A) X significantly predicts Y. B) X does not significantly predict Y. C) There is not enough information to answer this question. B) X does not significantly predict Y. C) There is not enough information to answer this question.
A) X significantly predicts Y.
92. Which of the following is not needed to compute the y-intercept using the method of least squares? A) My B) Mx C) Mxy D) the slope
C) Mxy
98. The more that the variability in ____ is associated with regression variation, the more likely it is that X predicts Y. A) XY B) X C) Y D) all of the above
C) Y
97. Both sources of variation in an analysis of regression measure the variability in A) X and Y B) X only C) Y only
C) Y only
72. An unanticipated variable not accounted for in a research study that could be causing or associated with observed changes in one or more measured variables is called A) reverse causality B) restriction of range C) a confound variable D) homoscedasticity
C) a confound variable
49. The Kruskal-Wallis test is the nonparametric analog to the A) one sample z test for a single population mean. B) two independent samples t test. C) one-way ANOVA F test. D) paired t test.
C) one-way ANOVA F test.
91. If b = -0.57, My = 2.75, and Mx = 5.25 for a set of data points, then what is the value of the y-intercept for the best-fitting linear equation? A) 0.24 B) 11.68 C) -0.24 D) 5.74
D) 5.74
32. Computing a one-way between-subjects ANOVA is appropriate when A) different participants are observed one time in each of two or more groups for one factor B) the same participants are observed in each of two or more groups for one factor C) the levels of one or more factors are manipulated D) all of the above
A) different participants are observed one time in each of two or more groups for one factor
51. The Kruskal-Wallis test relies on: A) ranked data B) raw data C) mean values D) all of the above
A) ranked data
90. If SSXY = -16.32 and SSX = 40.00 for a set of data points, then what is the value of the slope for the best-fitting linear equation? A) -0.41 B) -2.45 C) positive D) There is not enough information; you would also need to know the value of SSY.
A) -0.41
66. A researcher measures the following correlation: r = -0.21. What is the value of the coefficient of determination? A) 0.04 B) -0.04 C) 0.42 D) -0.42
A) 0.04
43. Which of the following is not a post hoc test for a one-way between-subjects ANOVA? A) F test for equal variance B) Fisher's LSD test C) Tukey's HSD test D) Bonferroni test
A) F test for equal variance
18. For an analysis of variance, the term "one-way" refers to A) the number of factors in the design B) the number of statistical tests in the design C) the number of ways that the data can be analyzed D) the direction that traffic should follow on a road
A) the number of factors in the design
117. The value of b1 and b2 are referred to as, A) unstandardized beta coefficients B) standardized beta coefficients C) regression variation D) residual variation
A) unstandardized beta coefficients
63. A researcher measures the relationship between narcissism and willingness to help. If SSXY = 240, SSX = 320, and SSY = 410, then what is the value of the correlation coefficient? A) 0.002 B) 0.02 C) 0.66 D) 0.69
C) 0.66
103. If the coefficient of determination is 0.30 and the sum of squares regression for an analysis of regression is 210, then what is the value of SSY? A) 210 B) 300 C) 490 D) 700
D) 700
Which of the following tests are not sensitive to extreme values? A. Spearman Correlation B. Chi Square Test C. Pearson Correlation D. Student's t-test E. A and B
E. A and B
Two different creams are used to treat athlete's foot. Each subject with this infection on both feet is given a treatment of Chavezcream on one foot while their other foot is treated with Chencream. What is the most appropriate statistical test to use in determining if there is a difference between the two treatments? a. McNemars' test b. Mann-Whitney U test c. Paired t-test d. Wilcoxon Signed-rank test
a. McNemars' test
111. A researcher computes the following analysis of regression table. Based on the data given, what is the value of the standard error of estimate? (Note: Complete the table first.) Source of Variation SS Df MS F Regression 28 1 5.60 Residual Total 118 19 A) 2.24 B) 5.00 C) 5.74 D) 8.49
A) 2.24
68. What is the problem with the following data for computing a correlation? Factor 1 Factor 2 3 3 3 3 3 3 3 3 3 3 A) The correlation coefficient will equal 0 because it violates the assumption of normality. B) The correlation coefficient will equal 1.0 because it violates the assumption of normality. C) The correlation coefficient will equal 0 because it violates the assumption of linearity. D) The correlation coefficient will equal 1.0 because it violates the assumption of linearity.
A) The correlation coefficient will equal 0 because it violates the assumption of normality.
100. The degrees of freedom associated with regression variation are equal to A) the number of predictor variables B) the number of predictor variables minus one C) n -1 D) n - 2
A) the number of predictor variables
84. 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 the above
A) the speed at which people eat
93. Which of the following is not needed to compute the slope using the method of least squares? A) SSY B) SSX C) SSXY
A) SSY
58. The following graphs display the data points for two linear correlations. Based on the information provided in these graphs, ________ displays a negative correlation and ________ displays a stronger correlation. A) Graph A; Graph B B) Graph B; Graph A C) Graph A; Graph A D) Graph B; Graph B
B) Graph B; Graph A
57. 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
17. The chi-square test assumes independence between observations. When the design is matched and we wish to compare two dichotomous variables, which test is appropriate? A) McNemar's test. B) The Goodness of Fit test. C) The Related Sample Sign test. D) Fisher's Exact test.
A) McNemar's test.
. A researcher conducts a chi-square goodness-of-fit test in which k = 3 and x^2 = 4.32. What is the decision for this test at a .05 level of significance? A) Retain the null hypothesis. B) Reject the null hypothesis. C) There is not enough information to answer this question.
A) Retain the null hypothesis.
Which of the following is appropriate for a Kruskal-Wallis test? A. A study on how how test anxiety affects actual test scores (IV: no anxiety, low-medium anxiety, high anxiety/DV: class ranking) B. A study on the impact of environment on rat development. (IV: impoverished, standard, or enriched housing/DV: # of tries it took to learn a maze) C. A study on how socioeconomic status affects attitude towards sales tax increases. (IV: working class, middle class, wealthy/DV: 5-pt Likert scale from strongly agree to strongly disagree) D. A study on the knowledge possessed by university students regarding US history. (IV: based on student's major/DV: exam score)
A. A study on how how test anxiety affects actual test scores (IV: no anxiety, low-medium anxiety, high anxiety/DV: class ranking) C. A study on how socioeconomic status affects attitude towards sales tax increases. (IV: working class, middle class, wealthy/DV: 5-pt Likert scale from strongly agree to strongly disagree)
23. What is the minimum number of groups that can be observed using the one-way between-subjects ANOVA design? A) 1 B) 2 C) 3 D) 4
B) 2
121. If F = 2.04 for the relative contribution of one factor, then what is this value when converted to a t statistic? A) 2.04 B) 1.43 C) 4.16 D) The conversion is not possible.
B) 1.43
102. If the coefficient of determination is 0.32 and SSY = 150, then what is the sum of squares residual for an analysis of regression? A) 48 B) 102 C) 150 D) There is not enough information to answer this question
B) 102
47. The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05. How many pairwise comparisons need to be made for this ANOVA result? A) 2 B) 3 C) 4 D) 12
B) 3
3. A genetics researcher expects 1:1:1:1 across four groups to align with Mendelian ratios.. If 200 people are tested, then what is the expected frequency for each group? A) 25 people B) 50 people C) 100 people D) 200 people
B) 50 people
30. A researcher assigned participants (n = 8 per group) to three dose groups. Different participants were assigned to each group and then assessed for a specific biomarker. What is the critical value for the one-way between-subjects ANOVA at a .05 level of significance? A) 3.07 B) 3.44 C) 3.47 D) 4.32
C) 3.47
54. A post-hoc test that can be used following a significant Kruskal-Wallis test is: A) Tukey's LSD test B) Bono U2 test C) Dunns Q test D) Duncin's HSD test
C) Dunns Q test
107. The standard error of estimate is used as a measure of the ________ in predictions using the equation of a regression line. A) linearity B) appropriateness C) accuracy D) certainty
C) accuracy
25. ANOVA stands for, A) analysis of variety B) analysis of variable attributes C) analysis of variance D) association of novel operating variable analyses
C) analysis of variance
37. A researcher conducts two studies on self-perception. In Study 1, 24 participants rate how positively they view themselves (on a 5-point scale) in one of three groups (n = 8 per group). In Study 2, the researcher conducts a similar study, except that k = 3 and n = 8. If SSB = 28 and SSE = 42 in both studies, then in which study will the decision be to reject the null hypothesis at a .05 level of significance for a one-way between-subjects ANOVA? A) Study 1 B) Study 2 C) both D) none
C) both
50. The Kruskal-Wallis test can be used to: A) compare a ranked outcome by race group (W, AA, Other). B) compare a skewed continuous variable by a categorical variable with four levels. C) compare an interval/ratio variable across more than two groups D) All of the above
D) All of the above
9. A chi-square goodness-of-fit test leads to a decision to retain the null hypothesis. Which of the following correctly explains this decision? A) frequencies observed were significantly different from frequencies expected at each level of the categorical variable B) frequencies observed were significantly different from frequencies expected across the levels of the categorical variable C) frequencies observed were significantly different from frequencies expected within and between expected frequencies D) Frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable
D) Frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable
20. A lowercase k is used to denote A) the number of groups in a study B) the number of participants in a study C) the number of levels of the factor in a study D) both A and C
D) both A and C
26. The degrees of freedom for the between-groups variability is called A) degrees of freedom numerator B) degrees of freedom denominator C) degrees of freedom between-groups D) both A and C
D) both A and C
10. When computing a chi-square goodness-of-fit test for a 2 x 2 table, the frequency expected in a given cell should never be less than A) the sample size B) the number of cells C) the frequency observed D) five
D) five
113. A statistical method that includes two or more predictor variables in the equation of a regression line to predict changes in a criterion variable is called A) analysis of variance B) standard error of estimate C) residual regression D) multiple regression
D) multiple regression
12. A researcher tests whether levels of education and income levels are related. In this study, he observes the following frequencies. If he computes a chi-square test for independence at a .05 level of significance, then what is the decision for this test? Education Level High Bachelor's Graduate Low Income 22 8 5 High Income 8 12 28 A) Education and income level are related. B) Education and income level are not related. C) Education and income level are independent. D) Both B and C are appropriate.
A) Education and income level are related.
38. A researcher computes the following one-way between-subjects ANOVA table. State the decision at a .05 level of significance. (Hint: Complete the table first.) Source of Variation SS df MS F Between groups 32 4 Within groups (error) 45 Total 122 A) Reject the null hypothesis. B) Retain the null hypothesis. C) Accept the null hypothesis. D) There is not enough information to answer this question.
A) Reject the null hypothesis.
123. The scores or data points for a regression analysis are typically reported in, A) a scatter plot B) a bar chart C) a pie chart D) all of the above
A) a scatter plot
22. Without changing the value of error variance, the ________ the between-groups variability, the more likely we are to reject the null hypothesis. A) larger B) smaller C) more homogeneous D) less spread
A) larger
95. Using an analysis of regression, the variability in Y that is predicted by X is measured by the A) regression variation B) residual variation C) correlation coefficient D) coefficient of determination
A) regression variation
116. For a multiple regression analysis with 2 and 12 degrees of freedom, MS regression is 135 and MS residual is 15. What is the decision for this test? A) reject the null hypothesis; the predictive variability of two predictor factors are significant B) retain the null hypothesis; the predictive variability of two predictor factors are not significant C) reject the null hypothesis; the predictive variability of one predictor factor is significant D) retain the null hypothesis; the predictive variability of one predictor factor is significant
A) reject the null hypothesis; the predictive variability of two predictor factors are significant
62. The correlation coefficient measures the extent to which changes in one factor are _______ in a second factor. A) related to changes B) causing changes C) causing variability D) all of the above
A) related to changes
77. The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between two ranked or ordinal variables is A) the Spearman correlation coefficient B) the point-biserial correlation coefficient C) the phi correlation coefficient D) none of the above
A) the Spearman correlation coefficient
53. The test statistic used for the Kruskal-Wallis test follows which distribution? A) the chi-square distribution with (k-1) degrees of freedom B) the t distribution with (k-1) degrees of freedom C) the F distribution with (1, k-1) degrees of freedom D) the standard normal distribution
A) the chi-square distribution with (k-1) degrees of freedom
When we have an outcome that is dichotomous and observed on a single set of subjects under two circumstances, what test is appropriate for testing for independence? A. McNemar's Test B. Chi-Square GOF test C. Chi-Square Test of Independence D. Fisher's Exact Test
A. McNemar's Test
35. A researcher randomly assigned 16 rodents to experience one of four levels of shock (n = 4 per group) following the illumination of a visual cue. If SSB = 24 and SSW = 48, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? A) Reject the null hypothesis. B) Retain the null hypothesis. C) There is not enough information to answer this question. D) Accept the null hypothesis
B) Retain the null hypothesis.
96. Using an analysis of regression, the variability in Y that is associated with error is measured by the A) regression variation B) residual variation C) correlation coefficient D) coefficient of determination
B) residual variation
106. An estimate of the standard deviation or distance that data points fall from the regression line is measured by the A) sum of squares B) standard error of estimate C) criterion variable D) predictor variable
B) standard error of estimate
14. If the expected frequencies equal to observed frequencies for a chi-square test for independence, what do we conclude? A) the degrees of freedom for the test are equal to 0 B) the test statistic value is equal to 0 C) the frequencies observed fit well with the frequencies expected D) both B and C
B) the test statistic value is equal to 0
Which combination of variables can you analyze using a single Pearson Correlation test? A. IT test grades and class ranking B. Age and Blood Pressure C. Blood sugar, cholesterol, and weight D. All of the above E. Only B and C
B. Age and Blood Pressure
83. A researcher measures the extent to which time spent watching educational preschool television programming predicts success in school. Which variable is the outcome variable in this example? A) educational preschool television B) type of television programming C) success in school D) time spent in school
C) success in school
34. Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean? A) that the population being sampled from is normally distributed B) that participants are randomly selected to participate in a sample C) that the variance is equal in each population from which samples are selected D) that one observation has no effect on the likelihood of another observation
C) that the variance is equal in each population from which samples are selected
122. To summarize any type of regression analysis, we report each of the following except the, A) test statistic B) degrees of freedom C) p value D) critical values
D) critical values
Pearson Correlation testing: A. Predicts how variable X would affect variable Y B. Looks at the relationship between two continuous variables C. Has d.f. of n - 2 D. All of the above E. Only B and C
E. Only B and C
99. Which of the following statements is true regarding the sources of variation present in an analysis of regression? A) Regression variation measures variability in X, whereas residual variation measures variability in Y. B) The closer that data points fall to the regression line, the more the variance in Y will be attributed to regression variation. C) There are three sources of variation in an analysis of regression: regression variance, residual variance, and error variance. D) When most of the variability in Y is associated with residual variation, then X predicts Y.
B) The closer that data points fall to the regression line, the more the variance in Y will be attributed to regression variation.
45. 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
104. In a sample of 22 participants, suppose we conduct an analysis of regression with one predictor variable. If F = 4.07, then what is the decision for this test at a .05 level of significance? A) X significantly predicts Y. B) X does not significantly predict Y. C) There is not enough information to answer this question
B) X does not significantly predict Y.
Drug X is a new medication to treat pain. 300 patients were separated into two groups and randomly assigned Drug X or a placebo. Pain scale was measured as still have pain or pain is gone. The pain scale was measured at 8 hours after drug administration. What statistical test is most appropriate to test whether there is a difference between the two groups? A. McNemars' Test B. Chi-square Test C. Fisher's Exact Test D. ANOVA
B. Chi-square Test
28. A researcher compares differences in creatinine between participants in a three treatment groups. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA? A) (2, 12) B) (3, 43) C) (2, 42) D) (3, 12)
C) (2, 42)
64. A researcher measures the relationship between two variables, X and Y. If SSXY = 340 and SSXSSY = 320,000, then what is the value of the correlation coefficient? A) 0.32 B) 0.34 C) 0.60 D) almost a zero correlation
C) 0.60
110. A researcher computes an analysis of regression in which MSE = 0.82. What is the value of se in this example? A) 0.67 B) 0.82 C) 0.91 D) There is not enough information to answer this question.
C) 0.91
87. Which of the following is used to determine the significance of predictions made by a best fitting linear equation? A) correlational analysis B) analysis of variance C) analysis of regression D) method of least squares
C) analysis of regression
To compute the expected frequencies for a chi-square test for independence, we use which of the following formulas? A) k - 1 B) p(n) C) (row total + column total)/grand total D) (row total X column total)/grand total
D) (row total column total)/grand total
44. Which of the following post hoc tests is associated with the greatest power to detect an effect? A) Schaffé test B) Tukey's HSD test C) Bonferroni test D) Fisher's LSD test
D) Fisher's LSD test
80. To summarize correlations, we report: A) the strength of the correlation B) the direction of the correlation C) the p value D) all of the above
D) all of the above
15. A researcher conducts two chi-square tests. The 2 × 2 chi-square was χ2 = 3.82. The 2 × 3 chi-square was χ2 = 5.02. Which chi-square test resulted in a decision to reject the null hypothesis at a .05 level of significance? A) the 2 × 2 chi-square B) the 2 × 3 chi-square C) both chi-square tests results in a decision to reject the null hypothesis D) none; both chi-square tests result in a decision to retain the null hypothesis
D) none; both chi-square tests result in a decision to retain the null hypothesis
Does physical exercise alleviate depression? We find some depressed people and check that they are all equivalently depressed to begin with. Then we allocate each person randomly to one of three groups: no exercise; 20 minutes of jogging per day; or 60 minutes of jogging per day. At the end of a month, we ask each participant to rate how depressed they now feel, on a Likert scale that runs from 1 ("totally miserable") through to 100 (ecstatically happy"). What test do we use? A. Chi-square B. McNemar C. ANOVA D. Kruskal-Wallis
D. Kruskal-Wallis
36. A researcher assigns 21 subjects to 3 treatment groups. An equal number of participants are assigned to each group. If F = 4.08 for this study, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? A) Reject the null hypothesis. B) Retain the null hypothesis. C) There is not enough information to answer this question. D) Do not reject the null hypothesis.
A) Reject the null hypothesis.
79. A researcher measures the correlation of the time it take participants to complete two tasks purported to measure the same cognitive skill. Participant times are converted to ranks from fastest to slowest. If ΣD2 = 165 and n = 20, then what is the decision for this correlation test? A) Retain the null hypothesis. B) Reject the null hypothesis. C) There is not enough information to answer this question.
B) Reject the null hypothesis.
39. A researcher computes the following one-way between-subjects ANOVA table for a study where k = 3 and n = 12. State the decision at a .05 level of significance. (Hint: Complete the table first.) Source of Variation SS df MS F Between groups 120 Within groups (error) Total 780 A) Reject the null hypothesis. B) Retain the null hypothesis. C) Accept the null hypothesis. D) There is not enough information to answer this question.
B) Retain the null hypothesis.
70. Which of the following is the assumption that the best way to describe the pattern of data is using a straight line? A) normality B) linearity C) homoscedasticity D) restriction of range
B) linearity
19. The term "between-subjects" refers to A) observing the same participants in each group B) observing different participants one time in each group C) the type of post hoc test conducted D) the type of effect size estimate measured
B) observing different participants one time in each group
76. The Spearman rank-order correlation coefficient is a measure of the direction and strength of the linear relationship between two ________ variables. A) nominal B) ordinal C) interval D) ratio
B) ordinal
40. In a study with four groups and 10 participants in each group, the sum of squares for the between-groups source of variation is 60. What is the value for the mean square between-groups in this study? A) 10 B) 15 C) 20 D) 1.67
C) 20
48. The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05. How many participants were observed in this study? A) 12 B) 37 C) 40 D) 39
C) 40
46. 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.
33. A researcher divides participants into groups that will engage in low, moderate, or intense levels of exercise. The total calories consumed by participants following the exercise are then recorded. What type of statistical design is appropriate for this study? A) a related samples t test B) a two-independent sample t test C) a one-way between-subjects ANOVA D) both B and C
C) a one-way between-subjects ANOVA
24. A researcher notes that the variability attributed to difference between group means is quite large. Which source of variation is the researcher referring to? A) between-persons B) within-groups C) between-groups D) error
C) between-groups
2. Which of the following is a statistical procedure used to test hypotheses about the discrepancy between the observed and expected frequencies in two or more nominal categories? A) related samples sign test B) paired t-test C) chi-square test D) all of the above
C) chi-square test
109. A researcher computes a perfect negative correlation, in which each data point falls exactly on the regression line. In this example, the value of the standard error of estimate will be A) less than 0 B) greater than 0 C) equal to 0 D) There is not enough information to answer this question.
C) equal to 0
67. The assumption that there is an equal variance or scatter of data points dispersed along the regression line is referred to as A) normality B) linearity C) homoscedasticity D) restriction of range
C) homoscedasticity
82. Select the description below that identifies the following correlation: r = .28, p < .01. A) the correlation is positive B) the correlation is statistically significant C) the coefficient of determination is .08 D) all of the above
D) all of the above
59. The numerator of the correlation coefficient measures the extent to which two variables A) vary together B) vary independently C) covary D) both A and C
D) both A and C
101. The degrees of freedom associated with residual variation are equal to A) the number of predictor variables B) the number of predictor variables minus one C) n - 1 D) n - 2
D) n - 2