Descriptive Statistics Numerical Ch3 (67-98)

67. The relative frequency of a class is computed by a. dividing the midpoint of the class by the sample size. b. dividing the frequency of the class by the midpoint. c. dividing the sample size by the frequency of the class. d. dividing the frequency of the class by the sample size. d ANSWER: 68. During a cold winter, the temperature stayed below zero for ten days (ranging from -20 to -5). The variance of the temperatures of the ten-day period a. is negative since all the numbers are negative. b. must be at least zero. c. cannot be computed since all the numbers are negative. d. can be either negative or positive. b ANSWER: 69. Which of the following is not a measure of variability? a. Mode b. Standard deviation c. Range d. Interquartile range ANSWER: a 70. If the coefficient of variation is 40% and the mean is 70, then the variance is a. 28. b. 2800. c. 1.75. d. 784. ANSWER: d 71. Given the following information: Standard deviation = 8 Coefficient of variation = 64% The mean would then be a. 12.5. b. 8. c. 0.64. d. 1.25. a ANSWER: 72. Since the mode is the most frequently occurring data value, it a. can never be larger than the mean. b. is always larger than the median. c. is always larger than the mean. d. none of these alternatives is correct. d ANSWER: 73. A group of students had dinner at a local restaurant. The total bill for the dinner was $414.70. Each student paid his/her equal share of the bill, which was $18.85. How many student’s were at the dinner? a. 4 b. 415 c. 19 d. 22 ANSWER: d 74. The standard deviation of a sample was reported to be 20. The report indicated that sample size? a. 16 b. 17 c. 18 d. 19 ANSWER: d 75. The variance of a sample was reported to be 144. The report indicated that size? a. 49 b. 50 c. 51 d. 52 ANSWER: = 7200. What is the = 7200. What is the sample c 76. From a population of size 1,000, a random sample of 100 items is selected. The mean of the sample a. must be 10 times smaller than the mean of the population. b. must be equal to the mean of the population, if the sample is truly random. c. must be 10 times larger than the mean of the population. d. can be larger, smaller or equal to the mean of the population. ANSWER: d 77. From a population of size 500, a random sample of 50 items is selected. The mode of the sample a. must be 500. b. must be equal to the mode of population, if the sample is truly random. c. must be equal to the mean of the population, if the sample is truly random. d. can be larger, smaller or equal to the mode of the population. d ANSWER: 78. From a population of size 400, a random sample of 40 items is selected. The median of the sample a. must be 200, since 400 divided by 2 is 200. b. must be 10, since 400 divided by 40 is 10. c. must be equal to the median of population, if the sample is truly random. d. none of these alternatives is correct. d ANSWER: 1 79. The geometric mean of 2, 4, 8 is a. 4.67. b. 5.0. c. 16. d. 4.0. d ANSWER: 80. The geometric mean of 1, 1, 8 is a. 10.0. b. 2.0. c. 3.33. d. 3.0. b ANSWER: 81. The geometric mean of 1, 3, 5, and 6 is a. 15.0. b. 5.0. c. 3.08. d. 3.75. c ANSWER: 82. The geometric mean of 1, 2, 4, and 10 is a. 2.99. b. 4.25. c. 17.0. d. 4.0. a ANSWER: 83. A researcher has collected the following sample data. 5 12 6 8 5 6 7 5 12 4 The 75th percentile is a. 7. b. 7.5. c. 8. d. 9. ANSWER: d 84. A researcher has collected the following sample data. The mean of the sample is 5. 3 5 12 3 2 The standard deviation is a. 8.944. b. 4.062. c. 13.2. d. 16.5. b ANSWER: 85. A researcher has collected the following sample data. The mean of the sample is 5. 3 5 12 3 2 The interquartile range is a. 2. b. 2.25. c. 6. d. 9. c ANSWER: 86. The following is the frequency distribution for the speed of a sample of automobiles traveling on an interstate highway. Speed (mph) 50 - 54 55 - 59 60 - 64 65 - 69 70 - 74 75 - 79 The mean is a. 35. b. 670. c. 10. d. 67. ANSWER: Frequency 2 4 5 10 9 5 35 d 87. The following is the frequency distribution for the speed of a sample of automobiles traveling on an interstate highway. Speed (mph) 50 - 54 55 - 59 60 - 64 65 - 69 70 - 74 75 - 79 The standard deviation is a. 6.969. b. 7.071. c. 48.570. d. 50.000. ANSWER: Frequency 2 4 5 10 9 5 35 b 88. The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day Stock Price 1 2 3 4 5 6 7 84 87 84 88 85 90 91 The mean is a. 84. b. 85. c. 86. d. 87. ANSWER: d 89. The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day 1 2 3 4 5 6 7 Stock Price 84 87 84 88 85 90 91 The mode is a. 84. b. 85. c. 86. d. 87. ANSWER: a 90. The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day 1 Stock Price 84 2 3 4 5 6 7 87 84 88 85 90 91 The median is a. 84. b. 85. c. 86. d. 87. ANSWER: d 91. The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day 1 2 3 4 5 6 7 Stock Price 84 87 84 88 85 90 91 The variance is a. 2.828. b. 8. c. 9. d. 81. ANSWER: b 92. Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers? a. Mean b. Median c. 2nd quartile d. 50th percentile ANSWER: a 93. The measure of variability easiest to compute, but seldom used as the only measure, is the a. range. b. interquartile range. c. standard deviation. d. variance. a ANSWER: 94. In computing descriptive statistics for grouped data, the data values in each class are approximated using the a. class lower limits. b. class upper limits. c. class midpoint. d. class range. c ANSWER: 95. Which of the following is not a measure of variability of a single variable? a. Range b. Covariance c. Standard deviation d. Interquartile range b ANSWER: 96. The empirical rule states that, for data having a bell-shaped distribution, the percentage of data values being within one standard deviation of the mean is approximately a. 33%. b. 50%. c. 68%. d. 95%. c ANSWER: 97. A box plot is a graphical representation of data that is based on a. the empirical rule. b. z-scores. c. a histogram. d. a five number summary. d ANSWER: 98. The coefficient of variation indicates how large the standard deviation is relative to the a. mean. b. median. c. range. d. variance. a ANSWER: