Chapter 03
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WebQuizzing – Ch. 03
Book ISBN-10 0538477490
Book ISBN-13 9780538477499
Author: Gerald Keller
Title: Statistics for Management and Economics
Ed: 9e
# Questions Submitted: 20 Multiple Choice
1. Which of the following statistics is a measure of central location?
A. The mean.
B. The median.
C. The mode.
D. All of these choices are true.
Analysis:
A. Incorrect. The mean is a measure of central location.
B. Incorrect. The median is a measure of central location.
C. Incorrect. The mode is a measure of central location.
D. Correct. All of these choices are true.
ANSWER: D Ref: Section 3.1
2. Which measure of central location is meaningful when the data are ordinal?
A. The mean.
B. The median.
C. The mode.
D. All of these choices are meaningful for ordinal data.
Analysis:
A. Incorrect. The mode is a meaningful measure of central location when the data are ordinal.
B. Incorrect. The mode is a meaningful measure of central location when the data are ordinal.
C. Correct. The mode is a meaningful measure of central location when the data are ordinal.
D. Incorrect. The mode is a meaningful measure of central location when the data are ordinal.
ANSWER: C Ref: Section 3.1
3. Which of the following statements about the mean is not always correct?
A. The sum of the deviations from the mean is zero.
B. Half of the observations are on either side of the mean.
C. The mean is a measure of the central location.
D. The value of the mean times the number of observations equals the sum of all
observations.
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Analysis:
A. Incorrect. Half of the observations are on either side of the mean is not always correct.
B. Correct. Half of the observations are on either side of the mean is not always correct.
C. Incorrect. Half of the observations are on either side of the mean is not always correct.
D. Incorrect. Half of the observations are on either side of the mean is not always correct.
ANSWER: B Ref: Section 3.1
4. Which of the following statements is true for the following observations: 7, 5, 6, 4, 7, 8, and
12?
A. The mean, median and mode are all equal.
B. Only the mean and median are equal.
C. Only the mean and mode are equal
D. Only the median and mode are equal.
Analysis:
A. Correct. The mean, median and mode are all equal.
B. Incorrect. The mean, median and mode are all equal.
C. Incorrect. The mean, median and mode are all equal.
D. Incorrect. The mean, median and mode are all equal.
ANSWER: A Ref: Section 3.1
5. In a histogram, the proportion of the total area which must be to the left of the median is:
A. exactly 0.50.
B. less than 0.50 if the distribution is negatively skewed.
C. more than 0.50 if the distribution is positively skewed.
D. unknown.
Analysis:
A. Correct. In a histogram, the proportion of the total area which must be to the left of the
median is exactly 0.50
B. Incorrect. In a histogram, the proportion of the total area which must be to the left of the
median is exactly 0.50
C. Incorrect. In a histogram, the proportion of the total area which must be to the left of the
median is exactly 0.50
D. Incorrect. In a histogram, the proportion of the total area which must be to the left of the
median is exactly 0.50
ANSWER: A Ref: Section 3.1
6. In a positively skewed distribution:
A. the median equals the mean.
B. the median is less than the mean.
C. the median is larger than the mean.
D. the mean can be larger or smaller than the median.
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Analysis:
A. Incorrect. In a positively skewed distribution the median is less than the mean.
B. Correct. In a positively skewed distribution the median is less than the mean.
C. Incorrect. In a positively skewed distribution the median is less than the mean.
D. Incorrect. In a positively skewed distribution the median is less than the mean.
ANSWER: B Ref: Section 3.1
7. Which of the following statements is true?
A. When the distribution is positively skewed, mean > median > mode.
B. When the distribution is negatively skewed, mean < median < mode.
C. When the distribution is symmetric and unimodal, mean = median = mode.
D. When the distribution is symmetric and bimodal, mean = median = mode.
Analysis:
A. Incorrect. It’s true that when the distribution is symmetric and unimodal, mean = median =
mode.
B. Incorrect It’s true that when the distribution is symmetric and unimodal, mean = median =
mode.
C. Correct. It’s true that when the distribution is symmetric and unimodal, mean = median =
mode.
D. Incorrect It’s true that when the distribution is symmetric and unimodal, mean = median =
mode.
ANSWER: C Ref: Section 3.1
8. The average score for a class of 30 students was 75. The 20 male students in the class
averaged 70. The 10 female students in the class averaged:
A. 75.
B. 85.
C. 65.
D. 70.
Analysis:
A. Incorrect. The 10 female students in the class averaged 85
B. Correct. The 10 female students in the class averaged 85
C. Incorrect. The 10 female students in the class averaged 85
D. Incorrect. The 10 female students in the class averaged 85
ANSWER: B Ref: Section 3.1
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9. The Empirical Rule states that the approximate percentage of measurements in a data set
(providing that the data set has a bell shaped distribution) that fall within two standard
deviations of their mean is approximately:
A. 68%.
B. 75%.
C. 95%.
D. 99%.
Analysis:
A. Incorrect. The Empirical Rule states 95%
B. Incorrect. The Empirical Rule states 95%
C. Correct. The Empirical Rule states 95%
D. Incorrect. The Empirical Rule states 95%
ANSWER: C Ref: Section 3.2
10. Which of the following types of data has no measure of variability?
A. Interval data
B. Nominal data
C. Bimodal data
D. None of these choices.
Analysis:
A. Incorrect. Nominal data has no measure of variability.
B. Correct. Nominal data has no measure of variability.
C. Incorrect. Nominal data has no measure of variability.
D. Incorrect. Nominal data has no measure of variability.
ANSWER: B Ref: Section 3.2
11. In a negatively skewed distribution, which of the following is the correct statement?
A. The distance from Q1 to Q2 is smaller than the distance from Q2 to Q3
B. The distance from the smallest observation to Q1 is larger than the distance from Q3 to the
largest observation
C. The distance from the smallest observation to Q2 is smaller than the distance from Q2 to
the largest observation
D. The distance from Q1 to Q3 is twice the distance from the Q1 to Q2
Analysis:
A. Incorrect. The distance from the smallest observation to Q1 is larger than the distance from Q3
to the largest observation.
B. Correct. The distance from the smallest observation to Q1 is larger than the distance from Q3
to the largest observation.
C. Incorrect. The distance from the smallest observation to Q1 is larger than the distance from Q3
to the largest observation.
D. Incorrect. The distance from the smallest observation to Q1 is larger than the distance from Q3
to the largest observation.
ANSWER: B Ref: Section 3.3
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12. Which of the following summary measures cannot be easily approximated from a box plot?
A. The range
B. The interquartile range
C. The second quartile
D. The standard deviation
Analysis:
A. Incorrect. The standard deviation cannot be easily approximated from a box plot
B. Incorrect. The standard deviation cannot be easily approximated from a box plot
C. Incorrect. The standard deviation cannot be easily approximated from a box plot
D. Correct. The standard deviation cannot be easily approximated from a box plot
ANSWER: D Ref: Section 3.3
13. Which measures of central location and variability are considered to be resistant to extreme
values?
A. The mean and standard deviation.
B. The mode and variance.
C. The median and interquartile range.
D. None of these choices.
Analysis:
A. Incorrect. The median and interquartile range are considered to be resistant to extreme values.
B. Incorrect. The median and interquartile range are considered to be resistant to extreme values.
C. Correct. The median and interquartile range are considered to be resistant to extreme values.
D. Incorrect. The median and interquartile range are considered to be resistant to extreme values.
ANSWER: C Ref: Section 3.3
14. Generally speaking, if two variables are unrelated (as one increases, the other shows no
pattern), the covariance will be:
A. a large positive number.
B. a large negative number.
C. a positive or negative number close to zero.
D. None of these choices.
Analysis:
A. Incorrect. If two variables are unrelated (as one increases, the other shows no pattern), the
covariance will be a positive or negative number close to zero.
B. Incorrect. If two variables are unrelated (as one increases, the other shows no pattern), the
covariance will be a positive or negative number close to zero.
C. Correct. If two variables are unrelated (as one increases, the other shows no pattern), the
covariance will be a positive or negative number close to zero.
D. Incorrect. If two variables are unrelated (as one increases, the other shows no pattern), the
covariance will be a positive or negative number close to zero.
ANSWER: C Ref: Section 4.4
15. The Y- intercept , b0 , of the least squares line ŷ  b0  b1 x represents the:
A. estimated average value of Y when X = 0.
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B. estimated average change in Y per unit change in X.
C. predicted value of Y.
D. variation around the sample regression line.
Analysis:
A. Correct. The Y- intercept , b0 , of the least squares line ŷ  b0  b1 x represents the estimated
average value of Y when X = 0.
B. Incorrect. The Y- intercept , b0 , of the least squares line ŷ  b0  b1 x represents the estimated
average value of Y when X = 0.
C. Incorrect. The Y- intercept , b0 , of the least squares line ŷ  b0  b1 x represents the estimated
average value of Y when X = 0.
D. Incorrect. The Y- intercept , b0 , of the least squares line ŷ  b0  b1 x represents the estimated
average value of Y when X = 0.
ANSWER: A Ref: Section 3.4
16. Which of the following is correct about the shape of a distribution?
A. The shape can show you how many modes there are.
B. The shape can help you determine the approximate center of the distribution.
C. The shape can help you determine whether the data are close or spread out.
D. All of the above choices are true.
Analysis:
A. Incorrect. All of the above choices are true.
B. Incorrect. All of the above choices are true.
C. Incorrect. All of the above choices are true.
D. Correct. All of the above choices are true.
ANSWER: D Ref: Section 3.1