class 7

Question 1

The statement “the percentage of cases scored below a given score” refers to:
a. Quartiles
b. Percentile
c. range
d. None of the above

Answer 1

b

Question 2

Mathematically, the standard deviation could be defined as:
a. The average of the sum of the absolute values of deviations around the mean
b. The average of the square root of the sum of the deviations around the mean
c. The square root of the average of the sum of squared deviations around the mean
d. The squared average of the sum of scores of a distribution

Answer 2

c

Question 3

True or false: A score is considered a potential outlier if it is greater or less than one and a half times the interquartile range.

Answer 3

true

Question 4

A ___________ is a score below which a given percentage of cases fall.
a. percentile
b. maximum
c. range
d. standard deviation

Answer 4

a

Question 5

The distance between the 25th and 75th percentile is known as ___________.
a. range
b. interquartile range
c. 50-th percentile
d. intermediate range

Answer 5

b

Question 6

True or false: When all scores in a population are the same, the standard deviation will always be
equal to zero.

Answer 6

true

Question 7

Each of the following is a characteristic of standard deviation, except:
a. The standard deviation is always positive.
b. The standard deviation is affected by the value of every score in a distribution.
c. The standard deviation is used to describe qualitative variables.
d. Standard deviations are almost always reported with the mean.

Answer 7

c

Question 8

True or false: variability can be negative.

Answer 8

false

Question 9

How many scores are included to compute the range?
a. Two scores; the largest and smallest score in a distribution.
b. Two scores; the 75-th and 25-th percentile.
c. Three scores, the 75-th, 50-th and 25-th percentile.
d. All the scores of a variable’s distribution.

Answer 9

a

Question 10

Suppose you know the minimum, the maximum, and the 25-th, 50-th, and 75-th percentiles of a distribution. Which of the following descriptive statistics can you determine?
a. mean and mode
b. interquartile range and mean
c. range and standard deviation
d. range and interquartile range

Answer 10

d

Question 11

Consider the following scores (from lowest to highest): 1, 2, 3, 4, 5, 6, 7, 8. What is the range?
a. range = 7
b. range = 8
c. range = 4.5
d. We do not have enough information to compute the range

Answer 11

a

Question 12

When data are divided into four equal parts, the data are split into________.
a. Bins
b. Ranges of grouped data
c. Quartiles
d. Interquartile ranges

Answer 12

c

Question 13

True or false. Sometimes, the range is smaller than the interquartile range.

Answer 13

false

Question 14

True or false: The sum of the differences of scores from their mean is zero.

Answer 14

true

Question 14

A description of the amount of variation in a variable is called ______.
a. average
b. dispersion
c. diffusion
d. differentiation

Answer 14

b

Question 15

A percentile reports the percentage of cases in a distribution ______.
a. above a given value
b. at a given value
c. below a given value
d. at or above a given value

Answer 15

c

Question 16

True or false: Dispersion describes the number of categories in a variable.

Answer 16

false

Question 17

True or false: A method of describing the dispersion of a variable that includes the minimum value, median, and maximum value is called the interquartile range.

Answer 17

false

Question 18

True or false: Mean, median, and mode are all measures of dispersion.

Answer 18

false

Question 19

A percentile point is ______.
a. the value of a score on a measurement scale below which a specified percentage of scores in a distribution fall
b. a summary display that distributes the sum of percentages across a series of intervals
c. an interval with no defined upper or lower boundary
d. the range of values contained in each interval of a grouped frequency distribution

Answer 19

a

Question 19

A student scores in the 80th percentile on an exam. What does this mean in comparison to all
other students?
a. The student scored higher than 80% of all others who took the exam.
b. The student scored worse than 80% of all others who took the exam.
c. Of all those who took the exam, only 80% of them completed it.
d. The student would score the same grade on the exam 80% of the time.

Answer 19

a

Question 20

Which of the following can be used to estimate the median?
a. the range
b. the 50th percentile
c. the mean
d. the mode

Answer 20

b

Question 21

A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of these data?
a. It is equal to zero because scores are approximately the same.
b. It is negative because 3 is less than the other scores in the distribution.
c. It is very small because scores are approximately the same.
d. It is very large because 3 is an outlier in the data.

Answer 21

c

Question 22

Which of the following is an example of a distribution with NO variability?
a. scores: 3, 5, 4, 4, 5, and 3
b. scores: 5, 5, 5, 5, 5, and 5
b. scores: 1, 2, 3, 4, 5, and 6
d. None of these; all distributions have at least some variability greater than 0.

Answer 22

b

Question 23

Which of the following distributions has the largest variability? a. scores: 1, 3, 6, 9, and 12 b. scores: 22, 24, 26, 28, and 30 c. scores: 2, 3, 4, 5, and 6 d. scores: 1, 2, 3, 4, and 5

Answer 23

a

Question 24

The range, a measure of variability, ______. a. is the difference between the largest and smallest value b. is especially informative when used to describe data sets without outliers c. includes only two values in its computation, regardless of the number of scores in a distribution d. all of these

Answer 24

d

Question 24

Regardless of the number of scores in a distribution, the range only includes ______ score(s) in its calculation. a. one b. two c. three d. the intermediate

Answer 24

b

Question 25

The range of scores between the upper and lower quartiles of a distribution is called the ______. a. median b. quartiles c. percentiles d. interquartile range

Answer 25

d

Question 26

A researcher decides to split scores on an exam into quartiles. She determines that a score of 64 is at the 25th percentile, a score of 74 is at the 50th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data? a. 16 b. 10 c. 6 d. There is not enough information to answer this question.

Answer 26

a

Question 27

The square root of the average squared distance of scores from the mean is called the ______. a. range b. interquartile range c. variance d. none of these

Answer 27

d

Question 28

The standard deviation can never be ______. a. zero b. negative c. smaller than the mean d. larger than the mean

Answer 28

b

Question 29

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 29

a

Question 30

True or false: A main disadvantage of computing a range is that it takes into consideration only two values regardless of the number of scores in a distribution.

Answer 30

true

Question 31

True or false: If all scores in a distribution are negative values, then the standard deviation will also be a negative value.

Answer 31

false

Question 32

Consider the following set of data: 80, 80, 80, 81, 81, 81, 81, 81, 81, 81, 82, 82, 83, 83, 83. How would you expect the standard deviation to change if we add a score equal to 70? a. The standard deviation gets smaller b. The standard deviation gets larger c. The standard deviation does not change, given that it is resistant to outliers d. The standard deviation does not change, due to its sensitivity to outliers

Answer 32

b