employees at the plants are also shown. These data are as follows: MEdiCEll $7,400 $14,400 $12,300 $6,200 $3,100 Employees 123 402 256 109 67 a. Compute the weighted mean medical payments for these ve plants using number of employees as the weights. b. Explain why Nike would desire that a weighted average be computed in this situation rather than a simple numeric average. 312. The Tru-Green Lawn Company provides yard care services for customers throughout the Denver area. The company owner recently tracked the time his eld employees spent at a sample of customer locations. He was hoping to use these data to help him with his scheduling and to establish billing rates. The following sample data, in minutes, were recorded: 31 27 29 22 24 30 28 21 29 26 22 17 17 20 38 10 38 25 27 23 23 13 17 34 25 29 22 22 14 1 l 29 26 29 29 37 32 27 26 18 22 Describe the central tendency of these data by computing the mean, median, and mode. Based on these measures, can you conclude that the distribution of time spent at customer locations is skewed or symmetric? 313. Eastern States Bank and Trust monitors its drive-thru service times electronically to ensure that its speed of service is meeting the company's goals. A sample of 28 drive-thru times was recently taken and is shown here. Speed of Service (time in seconds) 83 138 145 147 130 79 156 156 90 85 68 93 178 76 73 119 92 146 88 103 116 134 162 71 181 110 105 74 a. Compute the mean, median, and mode for these sample data. b. Indicate whether the data are symmetrical or skewed. c. Construct a box and whisker plot for the sample data. Does the box and whisker plot support your conclusions in part b concerning the symmetry or skewness of these data? 3-14. Todd Lindsey & Associates, a commercial real estate company located in Boston, owns six ofce buildings in the Boston area that it leases to businesses. The lease price per square foot differs by building due to location and building amenities. Currently, all six buildings are fully leased at the prices shown here. Price per Number of Square Foot Square F991 Building 1 $ 75 125,000 Building2 $ 85 37,500 Building 3 $ 90 77,500 Building 4 $ 45 35,000 Building 5 $ 55 60,000 Building 6 $1 10 130,000 a. Compute the weighted average (mean) price per square foot for these buildings. b. Why is the weighted average price per square foot preferred to a simple average price per square foot in this case? 3-15. Business Week recently reported that L. G. Philips LCD Co. would complete a new factory in Paju, South Korea. It will be the world's largest maker of liquid- crystal display panels. The arrival of the plant means that at-panel LCD televisions would become increasingly affordable. The average retail cost of a 20\" LCD television in 2000 was $5,139. To obtain what the average retail cost of a 37\" LCD was in 2008, a survey yielded the following data (in $U.S.): 606.70 558.12 625.82 533.70 464.37 511.15 400.56 538.20 531.64 632.14 474.86 567.46 588.39 528.78 610.32 564.71 912.68 475.87 545.25 589.15 Calculate the mean cost for these data. b. Examine the data presented. Choose an appropriate measure of the center of the data, justify the choice, and calculate the measure. c. The inuence an observation has on a statistic may be calculated by deleting the observation and calculating the difference between the original statistic and the statistic with the data point removed. The larger the difference, the more influential the data point. Identify the data points that have the most and the least influence in the calculation of the sample mean. 3-16. Wageweb. com exhibits salary data obtained from surveys. It provides compensation information on over 170 benchmark positions, including nance positions. It reports the salaries of chief nance ofcers for mid- sized rms. Suppose that a sample is taken of the annual salaries for 25 CFOs. Assume the data are in thousands of dollars. 9' 173.1 171.2 141.9 112.6 211.1 156.5 145.4 134.0 192.0 185.8 168.3 131.0 214.4 155.2 164.9 123.9 161.9 162.7 178.8 161.3 182.0 165.8 213.1 177.4 159.3 a. Calculate the mean salary of the CFOs. b. Based on measures of the center of the data, determine if the CFO salary data are skewed