Clinical Research Final Exam

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. 1.0 B. 2.0 C. 7.5 D. 10

2.0

he 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 mean age in this group? A. 11 years B. 16 years C. 19 years D. 20 years

20 years

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. 4.0 B. 3.23 C. 0.21 D. 1.68

3.23

In this distribution of ages, 11, 22, 24, 26, 13, 18, 16, 19, 30, 25, 16, what is the standard deviation? A. 3.48 years B. 5.62 years C. 5.90 years D. 34.80 years

5.90 years

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. 34% B. 47% C. 68% D. 95%

68%

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. 50th percentile B. 19th percentile C. 82nd percentile D. 69th percentile

69th percentile

A partial correlation is considered a zero-order correlation. True or False?

False

Negative correlations may be described as?

Indirect or inverse relationships

Which of the following is true about conducting a two-way ANOVA? A. Multiple comparisons are only necessary follow-up tests for main effects. B. Interaction effects should only be considered if main effects are significant. (NOT) C. The significance of a main effect is only considered if the interaction effect is significant. (NOT) D. Main effects may be ignored if there is a significant interaction effect.

Main effects may be ignored if there is a significant interaction effect.

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? sign test. A. Wilcoxon signed-ranks test. B. Mann-Whitney U test. C. Kruskal Wallis ANOVA.

Mann-Whitney U test

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. McNemar test B. Fisher exact test C. Chi-square

McNemar test

Of the three measures of central tendency, the _____________ is considered the most stable.

Mean

A paired t-test is a ratio of the? a. difference between group means divided by the common standard deviation of group means. b. difference between group means divided by the standard error of the difference between means. c. mean difference divided by the standard error of the mean difference. d. mean difference divided by the standard deviation of the mean difference.

Mean difference divided by the standard error of the mean difference.

r^2

Measure of the accuracy of prediction of Y tased on X.

Parameters

Measures if population characteristics.

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. Median C. Mode D. Standard deviation

Median

Measures of Central Tendency

Mode, mean, and median

In hypothesis testing, a Type II error occurs when the null hypothesis is? A. not rejected when it is true. B. rejected when it is true. C. not rejected when the alternative hypothesis is true. D. rejected when the alternative hypothesis is true.

Not rejected when the alternative hypothesis is true.

Advantages of Coefficient of Variation

- Expresses the standard deviation as a proportion of the mean, thereby accounting for differences in the magnitude of the mean. - It is independent of units of measurement because units will mathematically cancel out.

Are most Common Methods of Graphing Frequency Distributions

- Histogram - Line plot - Stem and leaf plot

The distributions can be described by 3 characteristics?

- Shape - Central tendency - Variability

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. .40 B. .006 C. .762 D. .238

.762

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. 0.10 B. 0.20 C. 0.40 D. 1.00

0.20

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. 1.106 B. 0.741 C. 0.782 D. 0.52

0.741

Choosing Nonparametric Tests

1. Data are measured on the nominal or ordinal scales. 2. Assumptions of population normality and homogeneity of variance cannot be satisfied.

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. 13.59% B. 34.13% C. 68.26% D. 10%

13.59%

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. 6 B. 5 C. 36 D. 15

15

In this distribution of ages, 11, 22, 24, 26, 13, 18, 16, 19, 30, 25, 16, what is the mode? A. 11 years B. 16 years C. 19 years D. 20 years

16 years

The ages 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 median age in this group? a. 11 years B. 16 years C. 19 years D. 20 years

19 Years

The degrees of freedom for chi-square associated with a 2 ´ 3 contingency table will be? A. 6 B. 2 C. 4 D. 3

2

Statistic

A descriptive index computed from sample data.

A study was done to compare three drugs on measures of pain following surgery. A multivariate analysis of variance was used to compare the drugs, resulting in a significant effect. Which of the following would be appropriate to determine which drugs are different from others? A. Logistic regression analysis B. Two-way analysis of variance C. Tukey's honestly significant difference D. A discriminant analysis

A discriminant analysis

All of the following describe an effect size index except for? A. a standardized ratio that estimates the degree to which the null hypothesis is false. B. a ratio of variance and sample size. C. an unitless ratio that allows comparison of results across studies. D. a ratio of the difference between groups and the variance within the groups

A ratio of variance and sample size.

Frequency Distribution

A table of rank ordered scores that shows the number of times each value occurred, or its frequency.

Line Plot

Also called frequency polygon, shows data points along a contiguous line.

Correlation is? a. a statistic to establish cause and effect. b. a process of estimating prediction accuracy of one variable for another. c. an estimate of shared variance between two variables. d. a method to compare two groups

An estimate of shared variance between two variables.

Descriptive Statistics

Are used to characterized the shape, central tendency, and variability within a set of data, often with the intent to describe a sample or population.

Percentiles

Are used to describe a score's position within a distribution relative to all other scores. Divide data into 100 equal portions.

Correlation Coefficients

Are used to quantitatively describe the strength and direction of a relationship between two variables.

Percentages

Are useful for describing distributions because they are independent of sample size.

In an exploratory factor analysis (EFA) factor loadings that indicate a variable belongs to a factor should be? A. less than .40 B. higher than .70 C. higher than .20 D. at least .40

At least .40

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? Between-groups = 4 df; Error = 46 df; Total = 50 df Between-groups = 3 df; Error = 46 df; Total = 49 df Between-groups = 2 df; Error = 47 df; Total = 49 df Between-groups = 3 df; Error = 47 df; Total = 50 df

Between-groups = 3 df; Error = 46 df; Total = 49 df

In 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 total sum of squares. C. within-groups sum of squares by the between-groups sum of squares. D. Between-groups sum of squares by the within-groups sum of squares.

Between-groups sum of squares by the total sum of squares.

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. True or False?

False

In a one-way repeated measures analysis of variance, the total variance is composed of? A. Between-subjects, main effect, and interaction effect variance. B. Between-groups variance and within-groups variance. C. Between-subjects variance, between-treatments variance, and error variance. D. Between-groups variance and within-subjects variance.

Between-subjects variance, between-treatments variance, and error variance.

Significance for the sign test is determined using the? A. t-distribution B. binomial distribution C. F distribution D. c2 distribution

Binomial distribution

Grouped Frequency Distribution

Can be constructed by grouping the scores into intervals, each representing a unique range of scores within the distribution.

What type of data are applied to a chi-square test? A. Ratio B. Categorical C. Continuous D. Ordinal

Categorical

Wilcoxon Signed-ranks Test

Comparison of two related samples. Paired t-test.

A factor matrix is rotated in a EFA to? A. change the orientation of variables to each other. B. extract additional factors. C. create a pattern that maximizes independent loadings on each factor. D. explain more variance than the original factor analysis.

Create a pattern that maximizes independent loadings on each factor.

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 = 2.37; the test is not significant. B. critical F = 2.53; the test is significant. C. critical F = 2.53; the test is not significant. D. critical F = 2.37; the test is significant.

Critical F = 2.53; the test is not significant.

Which of the following conditions does not warrant the use of nonparametric statistics? A. Data do not come from normal distributions. B. Data are at the interval level. C. Samples are very small. D. Data do not show homogeneity of variance across groups.

Data are at the interval level

Which of the following conditions does not warrant the use of nonparametric statistics? A. Samples are very small. B. Data are at the interval level. C. Data do not show homogeneity of variance across groups. D. Data do not come from normal distributions.

Data are at the interval level.

The main purpose of exploratory factor analysis is? A. correlation of variables. B. reduction of collinearity. C. confirmation of theory. D. data reduction.

Data reduction

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. True or False?

False

The purpose of cluster analysis is to? A. Determine if an intervention affects one group of patients more than another. B. Analyze data in a study that used cluster sampling to recruit participants. C. Establish which factors should be used as exclusion criteria in a study. D. Describe groupings of individuals in a sample that are similar on relevant characteristics.

Describe groupings of individuals in a sample that are similar on relevant characteristics.

Positive correlations are sometimes called?

Direct relationships.

The sign of the correlation coefficient indicates the ______________ of the relationship.

Direction

Quartiles

Divide a distribution into four equal parts.

To determine which variables should be assigned to a factor, the researcher will use? A. eigenvalues. B. factor loadings. C. communalitie. D. correlations

Eigenvalues

A correlation of .70 represents a strong relationship between two variables. True or False?

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. True or False?

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. True and False?

False

A significant chi-square test of independence indicates that there is a cause-and-effect relationship between the variables. True or False?

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. True or False?

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. True or False?

False

All outliers should be eliminated in a sample when describing correlation. True or False?

False

An advantage of chi-square is that it can be used with continuous data. True or False?

False

An effect size of d = 1.1 would be considered a small effect. True or False?

False

Following a two-way ANOVA, multiple comparisons are only used if there are significant differences in main effects. True or False?

False

If the variance in a sample of scores is 64, the standard deviation is 32. True or False?

False

In EFA, the names of factors are determined by the variable in each factor that has the highest loading. True or False?

False

In a one-way ANOVA, the total degrees of freedom equal the total number of participants in the sample. True or False?

False

In survival analysis, individuals who do not reach the terminal event during the study period are considered missing data. True or false?

False

Multiple comparisons for a one-way ANOVA are based on the t-test. True or False?

False

The Wilcoxon signed-ranks test and the sign test are both used with repeated measures. They will always result in the same conclusion. True or False?

False

The level of significance is the best way to determine the strength of a correlation coefficient. True our False?

False

In a factor analysis, variables can only belong to one factor. True or False?

Fase

All of the following are methods of graphic presentation of distributions of data except for? A. Frequency distribution B. Histogram C. Line plot D. Stem-and-leaf plo

Frequency Distribution

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?

Friedman ANOVA

The normal distribution is called a?

Gaussian distribution

The statistical estimate that indicates the risk of reaching the terminal event in a survival analysis is called? A. relative risk B. odds ratio C. sensitivity D. hazard ratio

Hazard ratio

A researcher studied the performance on a memory task in students who had <4 hours of sleep the night before versus 4-6, or >6 hours. The effect was also monitored for those who had high versus low reading skills. The graph above shows the distribution of scores among the 6 groups. The ANOVA showed a significant effect. Which of the following statements is not a reasonable interpretation of this result? A. There is an interaction between reading and hours sleep on memory score. B. There is an interaction effect present. C. Higher reading score with > 6 hours sleep produces the best memory score. D. High reading scores are associated with higher memory scores.

High reading scores are associated with higher memory scores.

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. the probability of committing a Type II error. C. if an effect size is sufficiently large that a statistically a significant result is probable. D. if a statistically significant outcome is clinically significant.

If a statistically significant outcome is clinically significant.

All of the following increase the width of a confidence interval except for? A. increased confidence level. B. increased variability. C. increased sample size. D. decreased sample size

Increased sample size.

r^2

Indicates the proportion of variance that is shared by two variables, or that portion of variance in Y that can be explained by knowing the variance in X.

For ordinal data what is the preferred measure of variability? A. Interquartile range B. Range C. Standard deviation D. Variance

Interquartile range

All three measures of central tendency can be applied to variables on the ______________ or ____________________ scales.

Interval , ratio

Stem and Leaf Plot

Is a grouped frequency distribution that is like a histogram turned on its side, but with individual values.

Friedman two-way ANOVA by Ranks

Is a nonparametric test to analyze data from a single-factor repeated measures design with three or more experimental conditions. - One-way repeated measures ANOVA

Histogram

Is a type of bar graph, composed of a series of columns, each representing one score or group interval.

Partial Correlation

Is a useful analytic tool for eliminating competing explanations for an association, thereby providing a clearer explanation of the true nature of an observed relationship and ruling out extraneous factors.

Box Plot

Is a useful way to visually demonstrate the spread of scores in a distribution, including the range, median and interquartile range.

Coefficient of Variation

Is another measure of variability that can be used to describe data measured on the interval to ratio scale.

Skewed Distribution

Is asymmetrical with fewer scores at one end forming a "tail."

Z-Score

Is computed by dividing the deviation of an individual score from the mean by the standard deviation.

Mann-Whitney U Test

Is one of the more powerful nonparametric procedures, designed to test the null hypothesis that two independent samples come from the same population.

Sign Test

Is one of the simplest nonparametric tests because it requires no mathematical calculations. It is based on the binomial distribution and does not require that measurements by quantitative.

Mean

Is the sum of a set of scores divided by the number of scores. Refer to as the "average".

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. It is reasonable to say that more than 25% of Americans are overweight. B. It is reasonable to say that more than 40% of Americans are overweight. C. The hypothesis that 33% of Americans are overweight cannot be rejected. D. It is reasonable to say that fewer than 40% of Americans are overweigh

It is reasonable to say that more than 40% of Americans are overweight.

The advantage of the median as a measure of central tendency is that?

It is unaffected by the value of extreme scores.

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 depends on sample size. C. It will stay the same. D. It will decrease.

It will increase.

The critical value for a two-tailed test is _________ than the critical value for a one-tailed test. A. smaller B. larger C. smaller or larger D. often larger but sometimes smalle

Larger

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. Mean difference D. Standard Error Difference

Levene's test

In an ANOVA, the value of F is calculated by? A. MSb / MSe B. SSe / dfe C. SSb / dfb D. SSb / SSe

MSb / MSe

In EFA, the number of factors in a dataset is usually determined by the? A. number of subjects represented in the dataset. B. cumulative eigenvalue of 1.0. C. number of variables in the dataset. D. rotated factor matrix

Number of variables in the dataset.

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 are usually large values in the distribution. D. Outliers can occur if measurement error occurs with a single participant.

Outliers are usually large values in the distribution

Many researchers prefer to use ______________ tests because they are considered more powerful.

Parametric

The ANOVA is based on all of the following assumptions except for? A. data should be drawn from populations with normal distributions. B. participants are chosen through a random sampling procedure. C. groups should show homogeneity of variance. D. data should be at the interval/ratio level.

Participants are chosen through a random sampling procedure.

Structural equation modeling verifies relationships among a set of variables, demonstrated using a? A. flow diagram. B. path diagram. C. cluster matrix. D. factor matrix.

Path diagram

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.

Planned comparisons require use of the Bonferroni adjustment.

A researcher wants to study the relationship between gender and heart rate. Which of the following correlation statistics should be used? A. Pearson product-moment correlation coefficient B. Kendall's tau C. Point biserial correlation b. Kendall's tau D. Spearman correlatio

Point biserial correlation b. Kendall's tau

Null and alternative hypotheses are statements about? A. population parameters. B. sample parameters. C. sample statistics. D. population and sample parameters

Populations parameters

Chi-square is used to look at the? A. Difference between frequencies in more than two groups. (not) B. Variance in categories. (not) C. Proportions of individuals in different categories. D. Difference between group means.

Proportions of individuals in different categories.

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. normal distribution of data. D. random assignment to groups.

Random assignment to groups

The simplest measure of variability is?

Range

Most nonparametric tests are based on?

Rank ordering of scores

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. Referring to findings from prior research on similar samples and variables. B. Using clinical judgment based on experience with similar patients. C. Referring to sample sizes used in prior research. D. Using a conventional effect size.

Referring to sample sizes used in prior research

Normal Curve

Refers to a specific type of bell-shaped curve where most of the scores fall in the middle of the scale and progressively fewer fall at the extremes.

Structural equation modeling (SEM) is a unique research approach as a non-experimental method. Which of the following statements is not true of SEM? A. SEM doesn't require any statistical procedures. B. SEM can identify direct and indirect effects, where some traits can be both causes and outcomes. C. SEM predicts causal relationships among a set of latent traits. D. SEM is based on a theoretical premise that shows how the traits should be related.

SEM doesn't require any statistical procedures.

Sampling error is the difference between the __________ and the ____________. A. sample mean; sample standard deviation b. population mean; population standard deviation C. sample mean; population mean D. sample standard deviation; population mean

Sample mean; population mean

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. Student-Newman-Keuls test B. Scheffé's comparison C. Fisher's Least Significant Difference D. The t-test

Scheffé's comparison

Sum of the Squared Deviation Scores

Shortened to sum of squares, will be larger as variability increases.

Negatively Skewed

Skewed to the left.

Positively skewed

Skewed to the right.

Standard Deviation

Square root of the variance.

The standard deviation is more useful as a descriptive measure than variance in a distribution because the? A. standard deviation is in the same units as the original data. C. variance is larger than the standard deviation. B. variance is influenced by sample size. D. variance is a population parameter.

Standard deviation is in the same units as the original data.

As sample size increases, the standard error of the mean? A. increases B. decreases C. stays the same D. increases or decreases

Stays the same

Deviation Score

Subtracting the mean from each score in the distribution.

Compared to their parametric counterparts, nonparametric statistics? A. Tend to have slightly lower power. B. Need larger samples. C. Can only used with ordinal data.

Tend to have slightly lower power

Range

Tends to increase with larger samples, making it an ineffective value for comparing distributions with different numbers of scores.

Nonparametric

Test hypotheses for group comparisons without normality or variance assumptions and are appropriate for analysis of normal or ordinal data.

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 significant, and there is a difference among the three types of training. B. The F value is not significant, but power may be low and differences may be present with a larger sample. C. The F value is not significant, and there is no difference in the three types of training. D. The F value is significant, and power is sufficient to demonstrate that the difference is meaningful.

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. The correlation of .14 did not occur by chance. B. There is a strong relationship between X and Y. C. Variable X causes variable Y. D. Variable X accounts for 14% of variance in variable Y.

The correction of .14 did to occur by chance.

A study is designed to look at the association between pain (absent, mild, severe) and sleep (poor, moderate, good), using a 3 x 3 contingency table. The result is χ2χ2 = 5.68. What is the critical value of χ2χ2 and is this a significant test at .05? A. The critical value is 3.84 and the test is not significant B. The critical value is 7.82 and the test is significant C. The critical value is 5.99 and the test is not significant. D. The critical value is 9.49 and the test is significant.

The critical value is 9.49 and the test is significant.

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. The decline in function or strength could be due to the individual's memory deficit. B. Declines in function are not related to declines in strength. C. A decrease in strength can cause a decline in function. D. A decrease in function can cause strength to decline.

The decline in function or strength could be due to the individual's memory deficit.

The sum of squares in a distribution is obtained by squaring? A. each value in the distribution and taking the sum. B. the mean from each score and taking the sum of those scores. C. the deviation scores and taking their sum. D. the mean.

The deviation scores and taking their sum.

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 the means for A and B will equal 1.0. B. The difference between means for A and B will equal zero. C. The mean for A will be greater than the mean for B. D. The difference between means for A and B will be greater than zero

The difference between means for A and B will equal zero.

Interquartile Range

The distance between the first and third quartiles, Q3 - Q1.

A study was done to compare the effect of four exercise routines on balance in patients with Parkinson's disease. Outcome measures include ability to stand on one foot for 30 seconds, walking speed, fear of falling, and score on the Dynamic Gait Index. The investigators chose to use a multivariate analysis of variance for this analysis because? A. the independent variable has four levels. B. the four dependent variables are related to each other. C. using an analysis of variance would decrease the power of the test. D. the independent variable has four levels

The four dependent variables are related to each other.

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 C. The mean is smaller than the mode B. The mean is equal to the median D. The mean is greater than the mode

The mean is smaller than the mode.

Mode

The most frequently occurring score(s) in a distribution

What is a parametric test analog for the nonparametric Kruskal Wallis analysis of variance? A. The unpaired t-test B. The paired t-test C. The one-way repeated measures of variance D. The one-way analysis of variance

The one-way analysis of variance

What is a parametric test analog for the nonparametric Friedman two-way analysis of variance by ranks? A. The paired t-test B. The unpaired t-test C. The one-way analysis of variance D. The one-way repeated measures of variance

The one-way repeated measures of variance

What is a parametric test analog for the nonparametric Sign 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

The paired t-test

What is a parametric test analog for the nonparametric Wilcoxon signed-ranks test? A. The unpaired t-test B. The one-way repeated measures of variance C. The one-way analysis of variance D. The paired t-test

The paired t-test

The major disadvantage of nonparametric test is that?

They generally cannot be adapted to complex clinical designs, such as factorial designs and tests of interactions.

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. the r2 for the relationship between diet and weight. B. the partial correlation of diet and weight with the effect of exercise removed. C. the zero-order correlation of weight and exercise. D. scatterplot of weight and exercise frequency.

The partial correlation of diet and weight with the effect of exercise removed.

The calculation of statistical power involves all of the following except for? A. the alpha level of significance B. the probability level (p) C. effect size D. number of subje

The probability level (p)

Researchers follow a group of patient who had a stroke who are independent living at home. They are interested in the rate of institutionalization, looking at the rate of institutionalization (long term care) versus maintaining independence over three years post-stroke, to see if there was a difference between those with and without cardiac complications. Results are shown in the survival plot. Which of the following statements is not an accurate interpretation of these data? A. Individuals with and without cardiac complications have a similar probability of maintaining independence until 1 year post-stroke. B. At two years post-stroke, those with cardiac complications have a 10% probability of being independent. C. The probability of maintaining independence is increased over time. D. For those without cardiac complications, there is a 50% probability that a patient will still be independent after 2 years.

The probability of maintaining independence is increased over time.

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. there is an association between gender and the presence of migraine headaches. B. There is no difference between the number of men and women with migraine headaches. C. There is no difference between the number of individuals with and without migraine headaches. D. The proportion of men or women with or without migraines will not be different from what would be expected by chance.

The proportion of men or women with or without migraines will not be different from what would be expected by chance.

Correlation coefficients can provide information on all of the following except for? A. the relationship between two variables that are measured in different units. B. whether there is a direct or inverse relationship between two variables. C. the degree of shared variance between two variables. D. the relationship between variables that have a quadratic relationship

The relationship between variables that have a quadratic relationship

Which of the following assumptions is not relevant for the unpaired t-test? A. The dependent variable should be derived from a population with a normal distribution. B. The variance in groups being compared should not be significantly different. C. The data should be at the interval/ratio measurement scale. D. The sample being tested should come from a random sampling of cases

The sample being tested should come from a random sampling of cases.

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 6.8 pounds. B. We are 95% confident that the mean of the population is 6.8 pounds. C. We are 95% confident that the sample mean is between 6.2 and 7.4 pounds. D. The sample mean is unknown.

The sample mean is 6.8 pounds.

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. Both variables should be measured at the interval/ratio level. B. The sample should be large enough to demonstrate at least 80% power. C. The scatterplot should show linearity. D. The variables should come from normal distributions.

The sample should be large enough to demonstrate at least 80% power.

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. there is no relationship between quality of life and age. B. it is not significant. C. it is a negative relationship. D. the sample was probably homogenous on age and quality of life

The sample was probably homogenous on age and quality of life

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 significant difference may be due to the sample size. C. The power of the study was too small to see a bigger effect size. D. The effect size would be larger if the sample was bigger.

The significant difference may be due to the sample size.

Which of the following is true about the calculation of sample variance? A. The sum of squares is not influenced by sample size B. The sum of squares is equal to zero for a normal distribution C. The sum of squares is divided by the sample size minus one D. The value for the sample variance is equal to the value of the population variance

The sum of squares is divided by the sample size minus one.

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 be significant at a lower p value. B. There would be no difference in the results. C. The test would no longer be significant. D. The test would be significant with a larger effect size

The test would no longer be significant.

Distribution

The total set of scores for a particular variable.

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 a = .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 not really different. B. There is a 4% chance that the groups are 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.

There is a 4% chance that the groups are really different

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 B has a stronger effect than Drug A C. Drug A and Drug B are equally effective. B Drug A has a stronger effect than Drug B. D. There is no way to know if drug A is better than drug B

There is no way to know if drug A is better than drug B

Kruskal-Wallis Analysis of Variance

Three or more independent groups are compared. Is a nonparametric analog of the one-way analysis of variance. It is a powerful alternative to the ANOVA when variance and normality assumptions for parametric tests are not met.

Purpose of Correlation

To describe the association between two variables.

What is the purpose of a goodness-of-fit test? A. To identify differences between categorical variables. B. To determine if sample frequencies differ from population frequencies. C. To determine which categorical variables have the highest frequencies. D. To determine if there is a significant difference between a pattern of observed frequencies and the pattern that would be expected by chance.

To determine if there is a significant difference between a pattern of observed frequencies and the pattern that would be expected by chance.

By changing a level of significance from = .05 to = .01, a researcher is making it more difficult to commit a Type I error. True or False?

True

Fisher's exact test can be used as an alternative to chi-square when samples are small. True or False?

True

In a chi-square test, the sample data are considered observed frequencies. True or False?

True

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 or False?

True

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 or False

True

The Spearman correlation is used when scores are measured on an ordinal scale. True or False?

True

The appropriate multiple comparison procedure for Friedman and Kruskal-Wallis analyses is Dunn's multiple comparison. True or False?

True

The difference between exploratory factor analysis and cluster analysis is that cluster analysis looks at clusters of people rather than variables. True or False?

True

The familywise error rate is the probability of making at least one Type I error in a set of comparisons. True or False?

True

The null hypothesis can never be proven. True or False?

True

The purpose of Levene's test is to determine if the variance is equal among study groups.. True or False?

True

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 or False?

True

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 or False?

True

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 or False?

True

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. one-way repeated measures analysis of variance. B. two-way analysis of variance. C. two-way analysis of variance with one repeated measure. D. one-way analysis of variance.

Two-way analysis of variance with one repeated measure.

Conducting multiple t-tests increases the likelihood of? A. finding correct conclusions. B. type I error C. type II error. D. measurement reliability

Type 1 error

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 I error, providing treatment when it is not needed. B. Type I error, not providing treatment when it is needed. C. Type II error, providing treatment when it is not needed. D. Type II error, not providing treatment when it is needed

Type I error, providing treatment when it is not needed.

What is a parametric test analog for the nonparametric Mann-Whitney U test?

Unpaired t-test

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. 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. B. 95% of all sample mean differences will fall within the range of 80 to 115. C. We are 95% confident that the mean difference for patients in this sample is between 80 and 115. D. We are 95% confident that the interval 80 to 115 contains the true population mean difference

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 all infants will weigh between 6.2 and 7.4 pounds. B. We are 95% confident that a randomly selected infant will weigh between 6.2 and 7.4 pounds. C. 95% of the time the mean birth weight of a sample will be 6.8 pounds. D. We are 95% confident that the population mean for birth weight is between 6.2 and 7.4 pounds.

We are 95% confident that the population mean for birth weight is between 6.2 and 7.4 pounds.

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 independent effect of the exercise routines on endurance? B. What is the combined effect of exercising 3x/week and 5x/week? C. What is the independent effect of program schedules on endurance? D. What is the combined effect of exercise routine and program schedule on endurance?

What is the combined effect of exercising 3x/week and 5x/week?

Compared to the width of a 95% confidence interval, the width of a 99% confidence interval is? A. Wider B. Narrower C. The same D. Unknown

Wider

The sum of deviation scores will always equal ____________ ?

Zero

The simple correlation between X and Y is called?

Zero order correlation.

The effect size index for the t-test is? A. d B. s C. F D. p

d

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. df = 30 B. df = 58 C. df = 28 D. df = 29

df = 29

Generally, an _________ in sample size is needed to make a nonparametric test as powerful as an analogous parametric test.

increase

In hypothesis testing, we use a _________ to make an inference about a _________. A. sample statistic; population parameter C. population parameter; sample statistic B. sample statistic; population statistic D. population statistic; sample statistic

sample statistic; population parameter

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

t(24)= -2.5, p=.034, d=.34

The appropriate multiple comparison for a one-way repeated measures ANOVA is the? A. Tukey's honestly significant difference. B. Student-Newman-Keuls test. C. Scheffé's comparison. D. t-test.

t-test

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.

tend to have slightly lower power.

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. weak because it has a negative correlation. B. weak because the size of the coefficient is small. C. strong because the correlation is highly significant. D. strong because it has a negative correlation.

weak because the size of the coefficient is small.

For thee Mann-Whitney U test, the correlation coefficient is based on the ______________?

z score

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.

χ2χ2= 12.50: The distribution in the class is significantly different from the population, with more left-handed students than expected.