Statistical Methods and Analysis Quiz

Question 1

An education counselor records the number of high school graduates enrolled in community colleges, 4-year colleges, and universities. What scale of measurement is the type of college?

a. nominal
b. ordinal
c. interval
d. ratio

Answer 1

a. nominal

Question 2

A psychologist wants to know how many of her clients continue with therapy for at least 12 days. If she constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer her question?

a. a cumulative frequency distribution from the bottom up
b. a cumulative frequency distribution from the top down
c. a simple frequency distribution
d. a relative frequency distribution

Answer 2

b. a cumulative frequency distribution from the top down

Question 3

A professor grades 120 research papers and reports that the average score was 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%?

a. The sum of the differences is minimal.
b. The sum of the differences is 80%, the same as the mean.
c. The sum of the differences is equal to zero.
d. It is impossible to know without knowing each of the 120 scores.

Answer 3

c. The sum of the differences is equal to zero.

Question 4

Which of the following is the best explanation for why the standard deviation is almost always reported with the mean?

a. The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation.
b. The standard deviation is also a measure of central tendency, so it is important to report this value with the mean.
c. The mean and standard deviation estimate basically the same thing, so these values are typically reported together.
d. This is not true; the standard deviation is rarely reported with the mean.

Answer 4

a. The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation.

Question 5

A distribution of probabilities for random outcomes of a bivariate or dichotomous random variable is called a

a. binomial probability distribution.
b. distribution of expected values.
c. random variable distribution.
d. mathematical expectation.

Answer 5

a. binomial probability distribution

Question 6

A therapist has a goal to reduce the mean number of patient symptoms expressed for a particular disorder to two symptoms per day. Following therapy, she determines that the z score for 2 symptoms per day is 0. Assuming the data are normally distributed, did she reach her goal?

a. No, because the z score indicates 0 improvement.
b. No, because the z score is not negative (indicating a reduction in symptoms).
c. Yes; in fact, she actually reduced the mean number of symptoms to 0.
d. Yes, because a z score of 0 is the average, or mean.

Answer 6

d. Yes, because a z score of 0 is the average, or mean.

Question 7

Suppose that a researcher selects a sample of participants from a population. If the shape of the distribution in this population is positively skewed, then what is the shape of the sampling distribution of sample means?

a. approximately positively skewed
b. approximately negatively skewed
c. approximately normally distributed
d. there is not enough information to answer this question because the population mean and variance are not given

Answer 7

c. approximately normally distributed

Question 8

Increasing sample size will

a. increase the alpha level.
b. increase the likelihood of committing a Type I error.
c. increase the power of the decision.
d. all of these.

Answer 8

c. Increase the power of the decision.

Question 9

To compute a one-sample t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test?

a. The estimated standard error must be known.
b. The population variance must be known.
c. The sample size must be known.
d. The sample mean and sample variance must be known.

Answer 9

b. The population variance must be known.

Question 10

A professor compares scores on a competency exam among students at two times during a single semester. What type of t test is most appropriate for this study?

a. one-sample t test
b. two-independent-sample t test
c. related-samples t test
d. there is not enough information to answer this question

Answer 10

c. related-samples t test

Question 11

Which type of error is used to compute the confidence interval for two related samples selected from at least one population with an unknown variance?

a. standard error
b. estimated standard error
c. estimated standard error for the difference
d. estimated standard error for the difference scores

Answer 11

d. estimated standard error for the difference scores

Question 12

Computing a one-way between-subjects ANOVA is appropriate when ______.

a. different participants are observed one time in each of two or more groups for one factor
b. the same participants are observed in each of two or more groups for one factor
c. the levels of one or more factors are manipulated
d. all of the above

Answer 12

a. different participants are observed one time in each of two or more groups for one factor

Question 13

Which of the following correctly identifies each source of variation in the two-way between-subjects ANOVA?

a. two between-groups, one within-groups, and error
b. two within-groups, one between-groups, and error
c. two interactions, one main effect, and error
d. two main effects, one interaction, and error

Answer 13

d. two main effects, one interaction, and error

Question 14

Which of the following is the assumption that the best way to describe the pattern of data is using a straight line?

a. normality
b. linearity
c. homoscedasticity
d. restriction of range

Answer 14

b. linearity

Question 15

The point-biserial correlation coefficient is a measure of the direction and strength of the linear relationship between two variables, where ______.

a. one is continuous, and one is dichotomous
b. both variables are on an ordinal scale
c. one is at interval level or higher and one is ordinal
d. both variables are on a nominal scale

Answer 15

a. one is continuous, and one is dichotomous

Question 16

Which of the following statements is true regarding the sources of variation present in an analysis of regression?

a. Regression variation measures variability in X, whereas residual variation measures variability in Y.
b. The closer that data points fall to the regression line, the more the variance in Y will be attributed to regression variation.
c. There are three sources of variation in an analysis of regression: regression variance, residual variance, and error variance.
d. When most of the variability in Y is associated with residual variation, then X predicts Y.

Answer 16

b. The closer that data points fall to the regression line, the more the variance in Y will be attributed to regression variation.

Question 17

What is a key distinction between parametric tests and nonparametric tests in terms of scales of measurement?

a. Parametric tests are used for interval and ratio data, whereas nonparametric tests are used for nominal and ordinal data.
b. Parametric tests are used for ordinal and nominal data, whereas nonparametric tests are used for interval and ratio data.
c. Parametric tests are used for ordinal or interval data, whereas nonparametric tests are used for nominal data only.
d. There is no distinction; both types of tests are used to analyze data on any scale of measurement.

Answer 17

a. Parametric tests are used for interval and ratio data, whereas nonparametric tests are used for nominal and ordinal data.

Question 18

A chi-square goodness-of-fit test leads to a decision to retain the null hypothesis. Which of the following correctly explains this decision?

a. Frequencies observed were significantly different from frequencies expected at each level of the categorical variable.
b. Frequencies observed were significantly different from frequencies expected across the levels of the categorical variable.
c. Frequencies observed were significantly different from frequencies expected within and between expected frequencies.
d. Frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable.

Answer 18

d. Frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable.

Question 19

The sign test is used as a nonparametric alternative to which parametric test?

a. one-sample t test
b. two-independent-sample t test
c. related-samples t test
d. one-sample t test and related-samples t test

Answer 19

d. one-sample t test and related-samples t test

Question 20

The key advantage of measuring ranked data is that it minimizes ______ caused by outliers.

a. significance
b. effect size
c. variability
d. all of these

Answer 20

c. variability