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3. Annual survey of computer crimes. Refer to the 2010 CSI 4. Sound waves from a basketball. An experiment was con- Computer Crime and Security Survey, Exercise 1.19 ducted to characterize sound waves in a spherical cavity. (p. 15). Recall that 351 organizations responded to the sur- (American Journal of Physics, June , 2010.) A fully inflated vey on unauthorized use of computer systems. One of the basketball, hanging from rubber bands, was struck with a survey questions asked respondents to indicate the per- metal rod, producing a series of metallic sounding pings. centage of monetary losses attributable to malicious ac- Of particular interest were the frequencies of sound waves tions by individuals within the organization (i.e., resulting from the first 24 resonances (echoes). A mathe- malicious insider actions). The following histogram sum- matical formula, well known in physics, was used to com- marizes the data for the 144 firms who experienced some pute the theoretical frequencies. These frequencies monetary loss due to malicious insider actions. (measured in hertz) are listed in the table on page 36. Use a. Which measurement class contains the highest propor- a graphical method to describe the distribution of sound tion of respondents? frequencies for the first 24 resonances. b. What is the approximate proportion of the 144 organi- BBALL zations that reported a percentage monetary loss from malicious insider actions less than 20%? Resonance Frequency Resonance Frequency C. What is the approximate proportion of the 144 organi- I 979 13 4334 zations that reported a percentage monetary loss from 1572 14 4631 malicious insider actions greater than 60%? 3 d. About how many of the 144 organizations reported a 2113 15 4711 percentage monetary loss from malicious insider 4 2122 16 4993 actions between 20% and 30%? 5 2659 17 5130 0.4 6 2795 18 5210 7 0.35 3181 19 5214 8 3431 20 5633 0.3 9 3638 21 5779 0.25 - 10 3694 22 5836 11 4038 23 6259 Relative Frequency 0.2 - 12 4203 24 6339 0.15 Source: Russell, D.A. "Basketballs as spherical acoustic cavities". American Journal of Physics, 0.1 Vol. 48, No. 6, June 2010. (Table 1.) 0.05 - 20 40 60 80 100 Monetary Loss (%)5. Characteristics of a rock fall. In Environmental Geology 6. Crude oil biodegradation. Refer to the Journal of Petroleum (Vol. 58, 2009) computer simulation was employed to Geology (April, 2010) study of the environmental factors estimate how far a block from a collapsing rock wall will associated with biodegradation in crude oil reservoirs. bounce-called rebound length-down a soil slope. Based Exercise 2.18 (p. 37). Recall that amount of dioxide (mil- on the depth, location, and angle of block-soil impact ligrams/liter) and presence/absence of crude oil was deter- marks left on the slope from an actual rock fall, the fol- mined for each of 16 water specimens collected from a mine lowing 13 rebound lengths (meters) were estimated. Com- reservoir. The data are repeated in the accompanying table. pute the mean and median of the rebound lengths and a. Find the mean dioxide level of the 16 water specimens. interpret these values. Interpret this value. b. Find the median dioxide level of the 16 water speci- ROCKFALL mens. Interpret this value. 10.94 13.71 11.38 7.26 17.83 11.92 C. Find the mode of the 16 dioxide levels. Interpret this 11.87 5.44 13.35 4.90 5.85 5.10 6.77 value. d. Find the median dioxide level of the 10 water speci- Source: Paronuzzi, P. "Rockfall-induced block mens with no crude oil present. propagation on a soil slope, northern Italy". e. Find the median dioxide level of the 6 water specimens Environmental Geology, Vol. 58, 2009. with crude oil present. (Table 2.) BIODEG Dioxide Amount Crude Oil Present 3.3 No 0.5 Yes 1.3 Yes 0.4 Yes 0.1 No 4.0 No 0.3 No 0.2 Yes 2.4 No 2.4 No 1.4 No 0.5 Yes 0.2 Yes 4.0 No 4.0 No 4.0 No Source: Permanyer, A., et al. "Crude oil biodegradation and environmental factors at the Riutort oil shale mine, SE Pyrenees", Journal of Petroleum Geology, Vol. 33. No. 2, April 2010 (Table 1).1. Do social robots walk or roll? According to the United 2. Beach erosional hotspots. Beaches that exhibit high ero- Nations, social robots now outnumber industrial robots sion rates relative to the surrounding beach are defined as worldwide. A social (or service) robot is designed to enter- erosional hotspots. The U.S. Army Corps of Engineers tain, educate, and care for human users. In a paper pub- conducted a study of beach hotspots using an online ques- lished by the International Conference on Social Robotics tionnaire. Information on six beach hotspots was collected. (Vol. 6414, 2010), design engineers investigated the trend in Some of the data are listed in the table. the design of social robots. Using a random sample of 106 a. Identify each variable recorded as quantitative or social robots obtained through a web search, the engineers qualitative. found that 63 were built with legs only. 20 with wheels only, b. Form a pie chart for the beach condition of the six 8 with both legs and wheels, and 15 with neither legs nor hotspots. wheels. This information is portrayed in the accompanying C. Form a pie chart for the nearshore bar condition of the figure. six hotspots. a. What type of graph is used to describe the data? d. Comment on the reliability of using the pie charts to b. Identify the variable measured for each of the make inferences about all beach hotspots in the country. 106 robot designs. C. Use graph to identify the social robot design that is cur- Long-Term Beach Beach Nearshore Bar Erosion Rate rently used the most. Hotspot Condition Condition (miles/year) d. Compute class relative frequencies for the different Miami No dunes/flat Single, categories shown in the graph. Beach. FL shore parallel e. Use the results, part d, to construct a Pareto diagram for the data Coney Island, NY No dunes/flat Other 13 Surfside, CA Single, Robotic Limbs Categories Bluff/scarp 35 shore parallel N = 106 Monmouth Single dune Planar Not estimated 70 Beach, NJ 63 Ocean City. NJ Single dune Other Not estimated 60 Spring Lake, NJ Not observed Planar 14 50 - Source: "Identification and characterization of erosional hotspots." William & Mary Virginia Institute of Marine Science, U.S. Army Corps of Engineers Project Report, March 18, 2002. 40 Number of Robots 30 20 20 - 15 None Both Legs Wheels ONLY ONLY Types of Robotic Limbs
