QMB 3200 Final Exam Questions With 100% Correct Answers

QMB 3200 Final Exam Questions With 100% Correct Answers Suppose we have the following data: 12, 17, 13, 25, 16, 21, 30, 14, 16, and 18. To find the 10% trimmed mean, what numbers should be deleted from the calculation? - answer12 and 30 Which of the following is not resistant to the outliers in a data set? a. Median b. Mean c. Variance d. Interquartile range - answerb. mean The pth percentile is a value such that at least p percent of the observations are: - answerless than or equal to this value. Which of the following provides a measure of central location for the data? a. Mean b. Variance c. Mode d. Standard deviation - answera. mean When testing water for chemical impurities, results are often reported as BDL, that is, below detection limit. The following data set gives the measurements of the amount of lead in a series of water samples taken from inner-city households (ppm): 5, 7, 12, BDL, 10, 8, BDL, 20, 6 Which of the following is correct? a. The mean lead level in the water is about 10 ppm. b. The median lead level in the water is 8 ppm. c. The mean lead level in the water is about 8 ppm. d. The median lead level in the water is 7 ppm. - answerd. The median lead level in the water is 7 ppm. A student made scores of 85, 56, and 91 on her first three statistics tests. What score does she need to make on her next test to have an 80 test average? - answer88 Growth factors for the population of Dallas in the past five years have been 1, 2, 3, 4, and 5, respectively. The geometric mean is: - answer^5square root 120 A sample of 99 distances has a mean of 24 feet and a median of 21.5 feet. Unfortunately, it has just been discovered that an observation that was erroneously recorded as "30" actually had a value of "35." If we make this correction to the data, then: - answerthe median remains the same, but the mean is increased. A numerical value used as a summary measure for a sample, such as sample mean, is known as a: - answersample statistic. The measure of location that is most likely to be influenced by extreme values in a data set is the: - answermean A student was performing an experiment that compared a new high protein food to the old food for pigs. He found the mean weight gain for subjects consuming the new food to be 12.8 pounds with a standard deviation of 3.5 pounds. Later, he realized that the scale was out of calibration by 1.5 pounds (meaning that the scale weighed items 1.5 pounds more). What should be the summary measures, mean and standard deviation, for the subjects consuming the new food? - answerThe mean should be 11.3 and the standard deviation should remain unchanged. When a set of data has suspect outliers, which of the following is the referred measure of central tendency? - answermedian In a sample of 500 students whose mean height is 67.8 inches, 150 were women. If the mean height of the women was 63.0 inches, what is the mean height of the men in the sample? - answer69.9 The coefficient of variation formula - answerthe standard deviation divided by the mean and multiplied by 100. The summary statistics for the hourly wages of a sample of 130 system analysts are given below: Mean = 60 Range = 20 Mode = 73 Variance = 324 Median = 74 The coefficient of variation is equal to: - answer(square root 324/ 60 x100)= 30% If the variance of a data set is correctly computed with the formula using in the denominator, which of the following is true? a. The data set is a population. b. The data set is adjusted for skewness. c. The data set is too small. d. The data set is a sample. - answerd. The data set is a sample. In a sample of size five, the mean is 23 and four of the observations have the following deviations from the mean: -6, 2, 5, and 3. What is the value of the fifth observation? - answer-4 There are three executives in an office with age 56, 57, and 58. If a 57-year-old executive enters the room, then: - answerthe mean age will stay the same, but the variance will decrease. The difference between the largest and the smallest data values is the: - answerrange The interquartile range is: - answerthe difference between Q3 and Q1, the third and first quartiles. The standard deviation of a sample was reported to be 20. The report indicated that Σ (xi-x̄)^2 = 7200. What is the sample size? - answer20-1 = 19 The numerical value of the standard deviation can never be: - answernegative The interquartile range is used as a measure of variability to overcome the fact that the: - answerrange is comprised of extreme values. Given the following information: Standard deviation = 8 Coefficient of variation = 64% The mean is - answer8 / 64%= 12.5