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WebQuizzing – Ch.04Ch. 03Book ISBN-10 0538477490Book ISBN-13 9780538477499Author: Gerald KellerTitle: Statistics for Management and EconomicsEd: 9e# Questions Submitted: 20 Multiple ChoiceWhich of the following statistics is a measure of central location?The mean. The median.The mode.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 3.1Which measure of central location is meaningful when the data are ordinal?The mean.The median.The mode.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 Which of the following statements about the mean is not always correct?The sum of the deviations from the mean is zero.Half of the observations are on either side of the mean.The mean is a measure of the central location.The value of the mean times the number of observations equals the sum of all observations.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 Which of the following statements is true for the following observations: 7, 5, 6, 4, 7, 8, and 12?The mean, median and mode are all equal.Only the mean and median are equal.Only the mean and mode are equalOnly 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 3.1In a histogram, the proportion of the total area which must be to the left of the median is: exactly 0.50.less than 0.50 if the distribution is negatively skewed.more than 0.50 if the distribution is positively skewed.unknown.Analysis:A. Correct. In a histogram, the proportion of the total area which must be to the left of the median is exactly 0.50B. Incorrect. In a histogram, the proportion of the total area which must be to the left of the median is exactly 0.50C. Incorrect. In a histogram, the proportion of the total area which must be to the left of the median is exactly 0.50D. Incorrect. In a histogram, the proportion of the total area which must be to the left of the median is exactly 0.50ANSWER: A Ref: Section 3.1In a positively skewed distribution:the median equals the mean.the median is less than the mean.the median is larger than the mean.the mean can be larger or smaller than the median.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 3.1Which of the following statements is true? When the distribution is positively skewed, mean > median > mode.When the distribution is negatively skewed, mean < median < mode.When the distribution is symmetric and unimodal, mean = median = mode. 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 3.1The 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:75.85.65.70.Analysis:A. Incorrect. The 10 female students in the class averaged 85B. Correct. The 10 female students in the class averaged 85 C. Incorrect. The 10 female students in the class averaged 85D. Incorrect. The 10 female students in the class averaged 85ANSWER: B Ref: Section 3.1The 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:68%.75%.95%.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 3.2Chebysheff’s Theorem states that the percentage of measurements in a data set that fall within three standard deviations of their mean is:75%.at least 75%.89%.at least 89%.Analysis:A. Incorrect. Chebysheff’s Theorem states that the percentage is at least 89%B. Incorrect. Chebysheff’s Theorem states that the percentage is at least 89% C. Incorrect. Chebysheff’s Theorem states that the percentage is at least 89%D. Correct. Chebysheff’s Theorem states that the percentage is at least 89% ANSWER: D Ref: Section 4.2Which of the following types of data has no measure of variability?Interval dataNominal dataBimodal dataNone 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 3.2In a negatively skewed distribution, which of the following is the correct statement?The distance from to is smaller than the distance from to The distance from the smallest observation to is larger than the distance from to the largest observationThe distance from the smallest observation to is smaller than the distance from to the largest observationThe distance from to is twice the distance from the to Analysis:A. Incorrect. The distance from the smallest observation to is larger than the distance from to the largest observation.B. Correct. The distance from the smallest observation to is larger than the distance from to the largest observation. C. Incorrect. The distance from the smallest observation to is larger than the distance from to the largest observation.D. Incorrect. The distance from the smallest observation to is larger than the distance from to the largest observation.ANSWER: B Ref: Section 3.3Which of the following summary measures cannot be easily approximated from a box plot?The rangeThe interquartile rangeThe second quartileThe standard deviationAnalysis: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 3.3Which measures of central location and variability are considered to be resistant to extreme values?The mean and standard deviation.The mode and variance.The median and interquartile range.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 3.3Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be:a large positive number.a large negative number.a positive or negative number close to zero.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 4.4The Y- intercept ,, of the least squares line represents the:estimated average value of Y when X = 0.estimated average change in Y per unit change in X.predicted value of Y.variation around the sample regression line.Analysis:A. Correct. The Y- intercept ,, of the least squares line represents the estimated average value of Y when X = 0. B. Incorrect. The Y- intercept ,, of the least squares line represents the estimated average value of Y when X = 0. C. Incorrect. The Y- intercept ,, of the least squares line represents the estimated average value of Y when X = 0. D. Incorrect. The Y- intercept ,, of the least squares line represents the estimated average value of Y when X = 0.ANSWER: A Ref: Section 3.4Which of the following is a property of r, the coefficient of correlation?r always lies between 0 and 1.r has no units.If you switch the values of X and Y, the sign of r changes.All of these choices are true.Analysis:A. Incorrect. r has no units is a property of r, the coefficient of correlation.B. Correct. r has no units is a property of r, the coefficient of correlation. C. Incorrect. r has no units is a property of r, the coefficient of correlation. D. Incorrect. r has no units is a property of r, the coefficient of correlation.ANSWER: B Ref: Section 4.4Which of the following is a property of the slope, b1? The slope equals one if X and Y have the same variance.The slope has the same sign as r, the coefficient of correlation.The slope equals one if r equals one.All of these choices are true.Analysis:A. Incorrect. The slope has the same sign as r, the coefficient of correlation is a property of the slope, b1.B. Correct. The slope has the same sign as r, the coefficient of correlation is a property of the slope, b1. C. Incorrect. The slope has the same sign as r, the coefficient of correlation is a property of the slope, b1. D. Incorrect. The slope has the same sign as r, the coefficient of correlation is a property of the slope, b1. ANSWER: B Ref: Section 4.4The denominator in the calculation of the sample covariance, cov (x,y), is:n – 2n – 1n2n – 1Analysis:A. Incorrect. The denominator in the calculation of the sample covariance, cov (x,y), is n – 1B. Correct. The denominator in the calculation of the sample covariance, cov (x,y), is n – 1 C. Incorrect. The denominator in the calculation of the sample covariance, cov (x,y), is n – 1 D. Incorrect. The denominator in the calculation of the sample covariance, cov (x,y), is n – 1ANSWER: B Ref: Section 4.4Which of the following is correct about the shape of a distribution?The shape can show you how many modes there are.The shape can help you determine the approximate center of the distribution.The shape can help you determine whether the data are close or spread out.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 ................
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