Research 1 Final
TRUE OR FALSE: Nonlinear regression can be used to analyze predictors when X and Y are related using a quadratic curve.
TRUE
TRUE OR FALSE: The Spearman correlation is used when scores are measured on an ordinal scale.
TRUE
TRUE OR FALSE: The appropriate multiple comparison procedure for Friedman and Kruskal-Wallis analyses is Dunn's multiple comparison.
TRUE
TRUE OR FALSE: The unpaired t-test is based on a ratio of the difference between group means divided by the standard error of the difference between means.
TRUE
TRUE OR FASLE: Fisher's exact test can be used as an alternative to chi-square when samples are small.
TRUE
TRUE OR FALSE: The level of significance is the best way to determine the strength of a correlation coefficient.
FALSE
Which of the following is true about the calculation of sample variance? A. The sum of squares is divided by the sample size minus one B.The sum of squares is equal to zero for a normal distribution C. The sum of squares is not influenced by sample size D.The value for the sample variance is equal to the value of the population variance
A. The sum of squares is divided by the sample size minus one
A researcher uses chi-square to examine the association between gender and the presence of migraine headaches. The null hypothesis for this study would be ... A. the proportion of men or women with or without migraines will not be different from what would be expected by chance. B. there is an association between gender and the presence of migraine headaches. C. there is no difference between the number of men and women with migraine headaches. D. there is no difference between the number of individuals with and without migraine headaches.
A. the proportion of men or women with or without migraines will not be different from what would be expected by chance.
As the distance of group means from the grand mean gets larger, what happens to the value of F? A.It will increase. B. It will stay the same. C. It will decrease. D. It depends on sample size.
A.It will increase.
A student receives a score of 82 on a standardized exam that has a mean of 77 and a standard deviation of 10. At what percentile does the student fall? A. 89th B. 69th C. 84th D. 50th
B. 69th
The value of R2 in a multiple regression analysis is ... A. The average correlation between each independent variable and the dependent variable. B. The amount of variance in Y that is explained by the full set of independent variables. C. The amount of variance in Y that is explained by the X variable with the highest correlation. C. A measure of collinearity.
B. The amount of variance in Y that is explained by the full set of independent variables.
The value of a sample mean is 85 and the standard deviation is 10. Assuming a normal distribution what percentage of scores will fall between 75 and 95? A. 95% B. 34% C. 47% D. 68%
D. 68%
TRUE OR FALSE: Multiple regression is used when more than one dependent variable is being tested.
FALSE
The degrees of freedom for chi-square associated with a 2 ´ 3 contingency table will be ... A. 4 B. 2 C. 3 D. 6
B. 2
TRUE OR FALSE: Dummy variables need to be created when using categorical variables in a regression equation. The number of dummy variables will always be one less than the number of categories.
TRUE
TRUE OR FALSE: By changing a level of significance from a = .05 to a = .01, a researcher is making it more difficult to commit a Type I error.
True
All of the following are methods of graphic presentation of distributions of data except for ... A. Stem-and-leaf plot B. Frequency distribution C. Line plot D. Histogram
B. Frequency distribution
TRUE OR FALSE: In a chi-square test, the sample data are considered observed frequencies.
TRUE
True or False: The null hypothesis can never be proven.
True
What is a parametric test analog for the nonparametric Sign test? A. The paired t-test B. The one-way analysis of variance C. The one-way repeated measures of variance D. The unpaired t-test
A. The paired t-test
Compared to the width of a 95% confidence interval, the width of a 99% confidence interval is ... A.narrower B. wider C. the same D. unknown
B. wider
A study is designed to examine the effect of exercise (against no exercise) on knee pain, with measurements taken at 1 week, 3 weeks, and 6 weeks. Participants are randomly assigned to one of the exercise conditions. The appropriate design would be.. A.none-way repeated measures analysis of variance. B. two-way analysis of variance. C. one-way analysis of variance. D. two-way analysis of variance with one repeated measure.
D. two-way analysis of variance with one repeated measure.
TRUE OR FALSE: An advantage of chi-square is that it can be used with continuous data.
FALSE
TRUE OR FALSE: The Wilcoxon signed-ranks test and the sign test are both used with repeated measures. They will always result in the same conclusion.
FALSE
TRUE OR FALSE: A chi-square test for goodness of fit is done to look at the distribution of strokes among people in four age groups. This test would have four degrees of freedom.
FALSE
How much variance in Y has been explained by X if r = .8? A. 16% B. 8% C. 64% D. 2%
C. 64%
Researchers studied the influence of having had a myocardial infarction (MI) and having hypertension (HTN) as predictors of the occurrence of stroke. The reported results of logistic regression are shown in the table above. Which of the following statements is an accurate interpretation of the data? A. The odds ratio associated with MI is significant. B. An individual who has HTN is about three times more likely to have a stroke as someone who does not have HTN. C. The odds ratio associated with HTN is not significant. D. An individual who had an MI is about 2 times less likely to have a stroke as someone who has not had an MI.
B. An individual who has HTN is about three times more likely to have a stroke as someone who does not have HTN.
A researcher decides to use stepwise regression with backward selection to determine which variables should enter the equation. Which of the following statements is true? A. The analysis will enter the X variable with the highest beta weight in the first step. B. The analysis will discard the one X variable with the lowest correlation with Y on the first step. C. The analysis will enter the X variable with the highest correlation with Y on the first step. D. The analysis will result in no X variables being entered into the equation.
B. The analysis will discard the one X variable with the lowest correlation with Y on the first step.
What is a parametric test analog for the nonparametric Wilcoxon signed-ranks test? A. The one-way analysis of variance B. The paired t-test C. The one-way repeated measures of variance D. The unpaired t-test
B. The paired t-test
A researcher is interested in establishing the relationship between quality of life and age. He recruits a sample of 30 patients in a skilled nursing facility. He finds a correlation of -.25 (p = .31). Most likely, the correlation is low because ... A. it is not significant. B. the sample was probably homogenous on age and quality of life. C. there is no relationship between quality of life and age. D. it is a negative relationship.
B. the sample was probably homogenous on age and quality of life.
An ordinal outcome measure is reported in a study. What is the preferred measure of central tendency to report for this outcome measure? A. Mean B. Mode C. Median D. Standard Deviation
C. Median
A researcher has studied the relationship between function and strength in individuals with dementia in a nursing care facility, finding a correlation of .75. Which of the following statements is a reasonable interpretation of this coefficient? A. A decrease in function can cause strength to decline. B. Declines in function are not related to declines in strength. C. The decline in function or strength could be due to the individual's memory deficit. D. A decrease in strength can cause a decline in function.
C. The decline in function or strength could be due to the individual's memory deficit.
All of the following describe an effect size index except for ... A. an unitless ratio that allows comparison of results across studies. B. a standardized ratio that estimates the degree to which the null hypothesis is false. C. a ratio of variance and sample size. D. a ratio of the difference between groups and the variance within the groups.
C. a ratio of variance and sample size.
In hypothesis testing, a Type II error occurs when the null hypothesis is A. not rejected when it is true. B. rejected when the alternative hypothesis is true. C. not rejected when the alternative hypothesis is true. D. rejected when it is true.
C. not rejected when the alternative hypothesis is true.
All of the following assumptions are important for the use of parametric statistics except for ... A.interval or ratio data. B. variances are homogeneous. C. random assignment to groups. D. normal distribution of data.
C. random assignment to groups
Which of the following statistics is not used as an effect size index for chi-square? A. w B. φ C. χ2
C. χ2
The box plots above represent two distributions. Which of the following statements is not an accurate interpretation of these plots? A.Group A has several outlier scores B.The interquartile range is larger in A than B C.The range of scores is larger in A than B. D. Both distributions have similar median, but A is less variable than B.
D. Both distributions have similar median, but A is less variable than B.
For ordinal data what is the preferred measure of variability? A. Variance B. Range C. Standard Deviation D. Interquartile Range
D. Interquartile Range
A test for goodness of fit is used to look at the distribution of handedness in children in a particular school. Assume that the distribution in the population is 80% right handed, 15% left handed, and 5% ambidextrous. In a class of 200 students, the distribution is 140 right handed, 45 left handed, and 15 ambidextrous. Using a = .05 as the level of significance, what is the correct result and conclusion for this analysis? A. χ2χ2= 5.99: The distribution in the class is not different from the population. B. χ2χ2= 0.875; The distribution in the class is not different from the population. C. χ2χ2= 125.00; The distribution in the class is significantly different from the population, with fewer right handed students than expected. D. χ2χ2= 12.50: The distribution in the class is significantly different from the population, with more left-handed students than expected.
D. χ2χ2= 12.50: The distribution in the class is significantly different from the population, with more left-handed students than expected.
TRUE OR FALSE: A correlation of .70 represents a strong relationship between two variables.
FALSE
TRUE OR FALSE: Multiple comparisons for a one-way ANOVA are based on the t-test.
FALSE
TRUE OR FALSE: A researcher is studying the effect of wearing a stabilizing belt on the severity of back pain in construction workers. He proposes a research hypothesis that pain will be less in those who wear the stabilizing belt than those who do not. In the analysis of this study, the researcher would use a two-tailed test.
False
In hypothesis testing, we use a _________ to make an inference about a _________. A. sample statistic; population statistic B. sample statistic; population parameter C. population statistic; sample statistic D. population parameter; sample statistic
B. sample statistic; population parameter
The sum of squares in a distribution is obtained by squaring A. each value in the distribution and taking the sum. B. the deviation scores and taking their sum. C. the mean from each score and taking the sum of those scores. D. the mean.
B. the deviation scores and taking their sum.
The interquartile range is A. equal to the variance. B. the difference between the first and third quartiles. C. the difference between the smallest and largest values. D. the 50th percentile.
B. the difference between the first and third quartiles.
A researcher looked at the relationship of age as a predictor of memory, using a memory test scored 1 to 100. The analysis resulted in an equation of Y = 10 + 0.66X. A 72 year old individual scored 85 on the test. Which statement is not an accurate conclusion? A. The predicted memory score would 58.5. B. The slope of the regression line would be .66. C. The residual for this individual would be small. D. This equation would underestimate the test score.
C. The residual for this individual would be small.
Which of the following assumptions is not relevant for the unpaired t-test? A. The variance in groups being compared should not be significantly different. B. The dependent variable should be derived from a population with a normal distribution. C. The data should be at the interval/ratio measurement scale. D. The sample being tested should come from a random sampling of cases.
D. The sample being tested should come from a random sampling of cases.
A researcher has established a correlation of -.29 (p = .002) between knee strength and weight in adults. Based on this outcome, the relationship between strength and weight is ... A. strong because it has a negative correlation. B. weak because it has a negative correlation. C. strong because the correlation is highly significant. D. weak because the size of the coefficient is small.
D. weak because the size of the coefficient is small.
TRUE OR FALSE: A good covariate for an ANCOVA will not have a linear relationship with the dependent variable
FALSE
TRUE OR FALSE: A partial correlation is considered a zero-order correlation.
FALSE
TRUE OR FALSE: A significant chi-square test of independence indicates that there is a cause-and-effect relationship between the variables.
FALSE
TRUE OR FALSE: All outliers should be eliminated in a sample when describing correlation.
FALSE
TRUE OR FALSE: Logistic regression is appropriately used when the outcome variable is continuous.
FALSE
TRUE OR FALSE: A researcher completes a study to compare two treatments and finds that there is a significant effect. She decides that one treatment is better than the other and rejects the null hypothesis. She may be making a correct decision or committing a Type II error.
False
TRUE OR FALSE: A researcher is designing a study and wants to establish the needed sample size. She would be using post hoc power analysis to make this decision.
False
TRUE OR FALSE: In a goodness of fit test for a uniform distribution, there is an assumption that the proportion of scores in each category will be the same.
TRUE
TRUE OR FALSE: The familywise error rate is the probability of making at least one Type I error in a set of comparisons.
TRUE
TRUE OR FALSE: The purpose of Levene's test is to determine if the variance is equal among study groups.
TRUE
TRUE OR FALSE: When doing a Student-Newman-Keuls comparison, the value of r for the q statistic will vary depending on the number of adjacent means included in the comparison
TRUE
A researcher designs a study to measure differences in anxiety (measured 1-10) in patients who do and do no receive an anxiety medication. The appropriate statistic for this analysis would be the ... A. Mann-Whitney U test. B. Wilcoxon signed-ranks test. C. Kruskal Wallis ANOVA. D. sign test.
A. Mann-Whitney U test.
What is a parametric test analog for the nonparametric Kruskal Wallis analysis of variance? A. The one-way analysis of variance B. The paired t-test C. The one-way repeated measures of variance D. The unpaired t-test
A. The one-way analysis of variance
A study is done to compare two drugs to improve blood pressure using a sample of 42 patients (21 in each group). The researcher hypothesized that drug 1 would be better than drug 2. The results of a t-test are as follows: t (40) = 1.684, p = .05. Using a = .05, the researcher concludes that there is a significant difference. What would be the effect if he had hypothesized that there would be a difference between the two drugs? A. The test would no longer be significant. B. There would be no difference in the results. C. The test would be significant with a larger effect size. D. The test would be significant at a lower p value.
A. The test would no longer be significant.
What is a parametric test analog for the nonparametric Mann-Whitney U test? A. The unpaired t-test B. The one-way analysis of variance C. The one-way repeated measures of variance D. The paired t-test
A. The unpaired t-test
A study was done to test the effect of four exercise routines and two program schedules on improving endurance. The two program schedules were 3x/week or 5x/week. Which of the following is not a question that can be answered in a two-way ANOVA? A. What is the combined effect of exercising 3x/week and 5x/week? B. What is the independent effect of program schedules on endurance? C. What is the independent effect of the exercise routines on endurance? D. What is the combined effect of exercise routine and program schedule on endurance?
A. What is the combined effect of exercising 3x/week and 5x/week?
In a regression analysis, the value of R2 tell us the ... A. amount of variance in X that can be explained by Y. B. size of the residual in predicting Y from X. C. correlation of X and Y. D. significance of the correlation between X and Y.
A. amount of variance in X that can be explained by Y.
An effect size for the independent samples one-way ANOVA analysis can be calculated by dividing the ... A. between-groups sum of squares by the total sum of squares. B. within-groups sum of squares by the between-groups sum of squares. C. between-groups sum of squares by the within-groups sum of squares. D. within-groups sum of squares by the total sum of squares.
A. between-groups sum of squares by the total sum of squares.
The significance of a regression line does not refer to ... A. significance of the regression constant. B. significance of the correlation coefficient associated with X and Y. C. slope of the line being significantly greater than zero. D. significance of F in an analysis of variance.
A. significance of the regression constant.
TRUE OR FALSE: An effect size of d = 1.1 would be considered a small effect.
false
What type of data are applied to a chi-square test? A. Ratio B. Continuous C. Categorical D. Ordinal
C. Categorical
TRUE OR FALSE: Following a two-way ANOVA, multiple comparisons are only used if there are significant differences in main effects.
FALSE
TRUE OR FALSE: In a one-way ANOVA, the total degrees of freedom equal the total number of participants in the sample
FALSE
TRUE OR FALSE: In the linear equation for a regression line, the coefficient b is called the constant.
FALSE
Conducting multiple t-tests increases the likelihood of ... A. type II error. B. type I error. C. finding correct conclusions. D. measurement reliability.
B. type I error.
The age in years of the individuals in a group is as follows: 11,22,24,26,13,18,16,19,30,25,16. What is the standard deviation age in this group? A. 5.9 B. 3.48 C. 34.8 D. 5.62
A. 5.9
Which of the following is true about conducting a two-way ANOVA? A. Main effects may be ignored if there is a significant interaction effect. B. The significance of a main effect is only considered if the interaction effect is significant. C. Interaction effects should only be considered if main effects are significant. D. Multiple comparisons are only necessary follow-up tests for main effects.
A. Main effects may be ignored if there is a significant interaction effect.
A researcher designs a study to show that a newly designed spirometer (A) can be substituted for the established model (B) for improving pulmonary function because it is cheaper to manufacture. The null hypothesis for this study would be that ... A. spirometer B will be more effective than spirometer A. B. spirometer A is no worse than spirometer B. C. there is no significant difference between spirometer A and B. D. spirometer A will be more effective than spirometer B.
A. spirometer B will be more effective than spirometer A.
Compared to their parametric counterparts, nonparametric statistics ... A. tend to have slightly lower power. B. do not use critical values to determine significance. C. need larger samples. D. can only used with ordinal data.
A. tend to have slightly lower power.
A study was designed to compare the level of wrist pain when using 2 different can openers in patients with arthritis. Participants were asked to use each can opener and estimate their level of discomfort, with the order of use randomly varied. The level of pain was measured on a visual analogue scale. The means for each can opener were Mean 1 = 8.3 (6) and Mean 2 = 4.0 (5). The standard deviation of difference scores was 8.2. What is the effect size for this test? A.0.782 B. 0.741 C. 0.524 D. 1.106
B. 0.741
A study is designed to test the effect of four different drugs on frequency of migraine headache in 50 patients. A one-way ANOVA was used to test the difference across four randomly assigned groups. In the ANOVA, which of the following degrees of freedom would be used with each source of variance? A. Between-groups = 3 df; Error = 47 df; Total = 50 df B. Between-groups = 3 df; Error = 46 df; Total = 49 df C. Between-groups = 4 df; Error = 46 df; Total = 50 df D. Between-groups = 2 df; Error = 47 df; Total = 49 df
B. Between-groups = 3 df; Error = 46 df; Total = 49 df
A study was done to test the difference in heart rate with four different exercises. A sample of 10 patients were tested, each using the four exercises in random order. The appropriate test for this study would be ... A. Wilcoxon signed-ranks test B. Friedman ANOVA C. Kruskal-Wallis ANOVA D. Mann-Whitney U test
B. Friedman ANOVA
To plan a study, a researcher must determine how large a sample to recruit. This requires estimating an effect size that should be achieved. Which of the following is not a strategy for estimating effect size? A. Using a conventional effect size. B. Referring to sample sizes used in prior research. C. Referring to findings from prior research on similar samples and variables. D. Using clinical judgment based on experience with similar patients.
B. Referring to sample sizes used in prior research.
The 95% confidence interval for the birth weight of 20 randomly selected infants is given as 6.2 and 7.4 pounds. Based on this confidence interval, which of the following statements is true? A. The sample mean is unknown. B. The sample mean is 6.8 pounds. C. We are 95% confident that the sample mean is between 6.2 and 7.4 pounds. D. We are 95% confident that the mean of the population is 6.8 pounds.
B. The sample mean is 6.8 pounds.
Two researchers are interested in the effects of drugs on reducing tremor in patients with Parkinson's disease. One researcher designs a study to compare drug A to a placebo, resulting in a significant difference at p =.04. A second researcher designs a study to compare drug B to a placebo, resulting in a significant difference at p =.002. Which of the following statements is correct? A. Drug A and Drug B are equally effective. B. There is no way to know if drug A is better than drug B. C. Drug A has a stronger effect than Drug B. D. Drug B has a stronger effect than Drug A.
B. There is no way to know if drug A is better than drug B.
What is the purpose of a goodness-of-fit test? A. To determine which categorical variables have the highest frequencies. B. To determine if there is a significant difference between a pattern of observed frequencies and the pattern that would be expected by chance. C. To identify differences between categorical variables. D. To determine if sample frequencies differ from population frequencies.
B. To determine if there is a significant difference between a pattern of observed frequencies and the pattern that would be expected by chance.
An unpaired t-test is used to compare two treatments on a sample of 100 patients, resulting in a mean difference of 98 and a 95% confidence interval of 80 to 115. Which of the following statements is a correct interpretation of this confidence interval? A. We are 95% confident that the mean difference for patients in this sample is between 80 and 115. B. We are 95% confident that the interval 80 to 115 contains the true population mean difference. C. If we performed this study on a different sample of 100 patients, there is a 95% chance the sample mean difference would be between 80 and 115. D. 95% of all sample mean differences will fall within the range of 80 to 115.
B. We are 95% confident that the interval 80 to 115 contains the true population mean difference.
Birth weights are measured for a sample of 20 infants. The 95% confidence interval for this distribution is from 6.2 to 7.4 pounds. Based on this confidence interval which of the following statements is correct? A.95% of the time the mean birth weight of a sample will be 6.8 pounds. B. We are 95% confident that the population mean for birth weight is between 6.2 and 7.4 pounds. C. 95% of all infants will weigh between 6.2 and 7.4 pounds. D. We are 95% confident that a randomly selected infant will weigh between 6.2 and 7.4 pounds.
B. We are 95% confident that the population mean for birth weight is between 6.2 and 7.4 pounds.
Significance for the sign test is determined using the A. χ2 B. binomial distribution C. t-distribution D. F distribution
B. binomial distribution
The square of the correlation coefficient r2 is called the ... A. regression coefficient. B. coefficient of determination. C. partial correlation. D. multiple correlation coefficient.
B. coefficient of determination.
Power analysis can be used to determine all of the following except for ... A. how many subjects are needed to carry out a study. B. if a statistically significant outcome is clinically significant. C. the probability of committing a Type II error. D. if an effect size is sufficiently large that a statistically a significant result is probable.
B. if a statistically significant outcome is clinically significant.
A paired t-test is a ratio of the ... A. mean difference divided by the standard deviation of the mean difference. B. mean difference divided by the standard error of the mean difference. C. difference between group means divided by the standard error of the difference between means. D. difference between group means divided by the common standard deviation of group means. mean difference divided by the standard deviation of the mean difference.
B. mean difference divided by the standard error of the mean difference.
Chi-square is used to look at the ... A. difference between frequencies in more than two groups. B. proportions of individuals in different categories. C. variance in categories. D. difference between group means.
B. proportions of individuals in different categories.
The appropriate multiple comparison for a one-way repeated measures ANOVA is the A. Scheffé's comparison. B. t-test. C. Student-Newman-Keuls test. D. Tukey's honestly significant difference.
B. t-test.
In a study involving eight groups, a researcher wants to maintain a familywise error rate of .05. What is the per comparison error rate for this study? A. .40 B. .25 C. .0018
C. .0018
There are 10 red marbles and 40 blue marbles in a jar. What is the probability that the first marble selected from the jar is a red marble? A. 0.40 B. 1.00 C. 0.20 D. 0.10
C. 0.20
When coding dichotomous independent variables for logistic regression, the typical format is ... A. 1 = the group without the adverse condition; 0 = the group with the adverse condition. B. 1 = the group with the more desirable condition; 0 = the group with the less desirable condition. C. 1 = the group with the more adverse condition; 0 = the group without the adverse condition. D. 1 = the group with the more adverse condition; 2 = the group without the adverse condition
C. 1 = the group with the more adverse condition; 0 = the group without the adverse condition.
In a multiple comparison test, the minimal significant difference (MSD) is used as the criterion to establish a significant difference between two means. A study is done using 24 subjects to compare four treatments, requiring six comparisons. The ANOVA has shown the following results: SSb = 150 and SSe = 80. What is the MSD for the Tukey comparison for this study? A. 0.21 B. 4.0 C. 3.23
C. 3.23
In a one-way repeated measures analysis of variance, the total variance is composed of ... A. Between-groups variance and within-groups variance. B. Between-groups variance and within-subjects variance. C. Between-subjects variance, between-treatments variance, and error variance. D. Between-subjects, main effect, and interaction effect variance.
C. Between-subjects variance, between-treatments variance, and error variance.
A study is designed to test if children of parents who smoke also smoke. In a sample of 1000 parent/child pairs, each was asked if they currently smoke. Data were recorded as yes/no. To analyze these data, we would need to use ... A. Chi-square B. A uniform goodness of fit test C. McNemar test D. Fisher exact test
C. McNemar test
What is a parametric test analog for the nonparametric Friedman two-way analysis of variance by ranks? A. The paired t-test B. The one-way analysis of variance C. The one-way repeated measures of variance D. The unpaired t-test
C. The one-way repeated measures of variance
A test to screen for a serious but curable disease is similar to hypothesis testing, with a null hypothesis of no disease, and an alternative hypothesis of disease. If the null hypothesis is rejected treatment will be given. Otherwise, it will not. Assuming the treatment does not have serious side effects, in this scenario it is better to increase the probability of making a ... A. Type II error, providing treatment when it is not needed. B. Type II error, not providing treatment when it is needed. C. Type I error, providing treatment when it is not needed. D. Type I error, not providing treatment when it is needed.
C. Type I error, providing treatment when it is not needed.
The intent of analysis of covariance (ANCOVA) in the comparison of two groups is to ... A. correlate the dependent variable values for the two groups. B. eliminate differences between groups on the dependent variable. C. adjust an outcome variable for differences in a covariate to make groups look similar on the dependent variable.
C. adjust an outcome variable for differences in a covariate to make groups look similar on the dependent variable.
The calculation of statistical power involves all of the following except for ... A.number of subjects B. the alpha level of significance C. effect size D. the probability level (p)
C. effect size
The standard deviation is more useful as a descriptive measure than the variance in a distribution because the A. variance is larger than the standard deviation B. variance is influenced by sample size. C. standard deviation is in the same units as the original data D. Variance is a population parameter
C. standard deviation is in the same units as the original data
Which of the following formats is correct for reporting the results of a t-test? A. t (35) = 12.34, p =.000, d = .87 B. t = 3.5, p < .05, d > .5 C. t (24) = -2.5, p = .034, d = .34 D. t (10) = 3.4, p > .05, n = 25
C. t (24) = -2.5, p = .034, d = .34
All of the following express a basic assumption for regression analysis except for ... A. a plot of standardized residuals that is spread around the zero point indicates that normality assumptions are met. B. the value of R2 indicates the proportion of variance in the dependent variable that is explained by the independent variables. C. the line of best fit will go through every point on the scatterplot. D. the regression line will minimize the sum of squared residuals.
C. the line of best fit will go through every point on the scatterplot.
A study has shown a correlation between diet (calories/day) and weight at r = .75. It also shows a correlation between exercise frequency and weight at r = .67. It would, therefore, be of interest to examine the correlation of diet and weight with the effect of exercise removed. This would require estimating ... A. scatterplot of weight and exercise frequency. B. the r2 for the relationship between diet and weight. C. the zero-order correlation of weight and exercise. C. the partial correlation of diet and weight with the effect of exercise removed.
C. the partial correlation of diet and weight with the effect of exercise removed.
TRUE OR FALSE: A distribution is composed of the following scores: 1, 1, 2, 7, 10, 10. The ranks associated with these scores would be 1, 1, 2, 3, 4, 4.
FALSE
TRUE OR FALSE: In a repeated measures ANOVA with three test conditions, the variance of differences between the test conditions is accounted for in the within-subjects source of variance.
TRUE
If a study involves eight groups, there would be a total of 28 possible pairwise comparisons. If the researcher tests each of the 28 comparisons at .05, what would be the familywise error rate for all pairwise comparisons? A. .762 B. .238 C. .006 D. .4
A. .762
A t-test is used to evaluate the difference in pain when individuals with back pain exercise with and without prior pain medication. 30 patients are tested on two consecutive days, with the testing condition randomly ordered. How many degrees of freedom would be associated with this test? A, 29 B. 30 C. 28 D.58
A. 29
A study is done to compare two intervention strategies, A and B, to determine which method patients prefer based on questionnaire responses. Which of the following statements is an accurate statement of the null hypothesis for this study? A. The difference between means for A and B will equal zero. B. The mean for A will be greater than the mean for B. C. The difference between the means for A and B will equal 1.0. D. The difference between means for A and B will be greater than zero.
A. The difference between means for A and B will equal zero.
An ANOVA is run to determine if there is a difference among five treatment groups for relief of shoulder pain in a sample of 65 patients. The analysis results in F = 2.41. The critical value and significance of this result is ... A. critical F = 2.53; the test is not significant. B. critical F = 2.37; the test is not significant. C. critical F = 2.37; the test is significant. D. critical F = 2.53; the test is significant.
A. critical F = 2.53; the test is not significant.
All of the following increase the width of a confidence interval except for ... A. increased sample size. B. increased confidence level. C. decreased sample size. D. increased variability.
A. increased sample size.
Which of the following conditions does not warrant the use of nonparametric statistics? A. Data do not show homogeneity of variance across groups. B. Samples are very small. C. Data are at the interval level. D. Data do not come from normal distributions.
C. Data are at the interval level.
All of the following refers to a difference between regression analysis and correlation except for ... A. regression allows for estimation of a line of best fit. B. regression enables prediction of the dependent variable. C. regression measures the strength of the association between two variables. D. regression provides an estimate of the amount of variance in Y explained by X.
C. regression measures the strength of the association between two variables.
A study is designed to estimate the difference in weight loss with two types of diets, A and B. A total of 1000 men who are overweight are recruited, 500 randomly assigned to each type of diet. The researcher finds that the difference in weight loss between the two groups is 5 pounds at p = .01, and concludes that diet A is better than diet B. Which of the following statements is accurate? A. The researcher may be committing a Type II error. B. The effect size would be larger if the sample was bigger. C. The power of the study was too small to see a bigger effect size. D. The significant difference may be due to the sample size.
D. The significant difference may be due to the sample size.
Correlation is ... A. a process of estimating prediction accuracy of one variable for another. B. a method to compare two groups. C. a statistic to establish cause and effect. D. an estimate of shared variance between two variables.
D. an estimate of shared variance between two variables.
As sample size increases, the standard error of the mean ... A.stays the same B. increases or decreases C. increases D. decreases
D. decreases
PageAll of the following can be used as effect size indices for the ANOVA except for ... A. f B. η2 C. ω2 D. p
D. p
TRUE OR FALSE: In defining probability and odds, probability is the likelihood of a particular event occurring out of all possible events; odds represent the ratio of the likelihood that a particular event will occur and the likelihood that it will not occur.
TRUE
TRUE OR FALSE: When using an unpaired t-test, the line for "Equal variance assumed" should be used if the probability associated with Levene's test is .09.
TRUE
A researcher wants to study the relationship between gender and heart rate. Which of the following correlation statistics should be used? A. Point biserial correlation B. Kendall's tau C. Pearson product-moment correlation coefficient D. Spearman correlation
A. Point biserial correlation
A study is done to test the null hypothesis that treatment with drug A is not more effective than drug B for reducing back pain using a VAS. Using =.05, a statistical test (an independent t-test) found that the difference between the means of the two groups was 6.7, and this was significant at p = .04. Which of the following statements is not a correct interpretation? A. There is a 4% chance that the groups are really different. B. There is a 4% chance that the groups are not really different. C. There is a 4% chance that we would find a difference as big as 6.7 even if the drugs were not different. D. If we repeated this study 100 times, we could expect to find 4 studies to show a significant difference just by chance.
A. There is a 4% chance that the groups are really different.
Correlation coefficients can provide information on all of the following except ... A. the relationship between variables that have a quadratic relationship. B. whether there is a direct or inverse relationship between two variables. C. the relationship between two variables that are measured in different units. D. the degree of shared variance between two variables.
A. the relationship between variables that have a quadratic relationship.
What should you look in output of an unpaired t-test for to determine if variances are equal across groups? A.Levene's test B.Confidence intervals C. Standard Error Difference D. Mean difference
A.Levene's test
The effect size index for the t-test is ... A. F B. d C. p D. s
B. d
Sampling error is the difference between the __________ and the ____________. population mean; population A. standard deviation B. sample mean; population mean C. sample standard deviation; population mean D. sample mean; sample standard deviation
B. sample mean; population mean
The value of a sample mean is 70 with a standard deviation is 10. What proportion of the sample has a score greater than 80? A. 34.13% B. 10% C.13.59% D. 68.26%
C. 13.59%
Which statement is not true about planned comparisons? A. Planned comparisons can include complex contrasts. B. Planned comparisons can be carried out even if the ANOVA is not significant. C. Planned comparisons require use of the Bonferroni adjustment. D. The researcher decides which comparisons will be made before the study is done.
C. Planned comparisons require use of the Bonferroni adjustment.
In an ANOVA, the value of F is calculated by ... Question 9 options: A. MSb / MSe B. SSe / dfe C. SSb / SSe D. SSb / dfb
C. SSb / SSe
A study was designed to compare three groups on balance scores following three types of balance training. 33 patients are randomly assigned to the two groups in a pretest-posttest design. An ANOVA resulted in F (2, 30) =3.25, p = .07, h2 = .09. What is your reasonable conclusion? A. The F value is not significant, and there is no difference in the three types of training. B. The F value is significant, and there is a difference among the three types of training. C. The F value is not significant, but power may be low and differences may be present with a larger sample. D. The F value is significant, and power is sufficient to demonstrate that the difference is meaningful.
C. The F value is not significant, but power may be low and differences may be present with a larger sample.
A correlation between two variables X and Y resulted in r = .14 (p = .001). Which statement is a valid conclusion? A. There is a strong relationship between X and Y. B. Variable X causes variable Y. C. The correlation of .14 did not occur by chance. D. Variable X accounts for 14% of variance in variable Y.
C. The correlation of .14 did not occur by chance.
In a negatively skewed distribution, which of the following best describes the relationship between the measures of central tendency? A. The mean is greater than the median B. The mean is equal to the median C. The mean is smaller than the mode D. The mean is greater than the mode
C. The mean is smaller than the mode
Which of the following is not a consideration in determining whether the Pearson correlation is an appropriate statistic to study the relationship between two variables? A. The scatterplot should show linearity. B. The variables should come from normal distributions. C. The sample should be large enough to demonstrate at least 80% power. D. Both variables should be measured at the interval/ratio level.
C. The sample should be large enough to demonstrate at least 80% power.
A researcher believes that an exercise program will be more effective for improving balance than a control activity. The alternative hypothesis (H1) for this study can be written as ... A.Xe=Xc B. Ue=Uc C. Ue>Uc D. Xe not equal to Xc
C. Ue>Uc
A researcher is studying the effect of six different drugs on arthritis pain. With a significant result, the researchers wants to know which drugs are better than others. How many pairwise comparisons would he need to make? A. 5 B. 36 C. 6 D. 15
D. 15
The value of a sample mean is 75 on a midterm examination and the standard deviation is 10. What is the z-score for a student who achieves a grade of 95? A. 1 B. 7.5 C.10 D.2
D. 2
Suppose a 95% confidence interval from a study sample for the proportion of Americans who are overweight is 0.29 to 0.37. Which one of the following statements is false? A. The hypothesis that 33% of Americans are overweight cannot be rejected. B. It is reasonable to say that fewer than 40% of Americans are overweight. C. It is reasonable to say that more than 25% of Americans are overweight. D. It is reasonable to say that more than 40% of Americans are overweight.
D. It is reasonable to say that more than 40% of Americans are overweight.
The critical value for a two-tailed test is _________ than the critical value for a one-tailed test. A. smaller B. often larger but sometimes smaller C. smaller or larger D. larger
D. Larger
Which of the following statements about outliers is not true? A. Outliers are values that are substantially different from the rest of the data. B. Outliers have an effect on regression parameters. C. Outliers can occur if measurement error occurs with a single participant. D. Outliers are usually large values in the distribution.
D. Outliers are usually large values in the distribution.
Researchers are planning a study of 4 drugs in the treatment of pancreatic cancer. They will do a one-way ANOVA, and want to plan on which multiple comparison will be used if the ANOVA is significant. Because these drugs have serious side-effects, they do not want to make a mistake in saying a drug is effective if it is not. Which multiple comparison would be the best choice? A. Fisher's Least Significant Difference B. Student-Newman-Keuls test C. The t-test D. Scheffé's comparison
D. Scheffé's comparison
The ANOVA is based on all of the following assumptions except for ... A. groups should show homogeneity of variance. B. data should be at the interval/ratio level. C. data should be drawn from populations with normal distributions. D. participants are chosen through a random sampling procedure.
D. participants are chosen through a random sampling procedure.
Null and alternative hypotheses are statements about ... A. sample parameters. B. sample statistics. C. population and sample parameters. D. population parameters.
D. population parameters.
Calling a regression line the "line of best fit" indicates that it will ... A. fit a theoretical model. B. show a perfect correlation between X and Y. C. be significant. D. result in the smallest sum of residuals for the scores.
D. result in the smallest sum of residuals for the scores.
TRUE OR FALSE: A study is done to compare two groups, with 25 participants randomly assigned to each group. The total degrees of freedom for this t-test is 25.
false
TRUE OR FALSE: A study is planned to determine the effectiveness of a mobilization technique in treating back pain. Participants are randomly assigned to two groups, one getting mobilization and the other getting active exercise. The paired t-test is the appropriate statistic for this analysis.
false
