Preface to First Edition - lib

46 SIMPLE INFERENCETable 3.1:roomwidth data (continued).unit width unit width unit width unit widthmetres 15 feet 30 feet 42 feet 60metres 15 feet 30 feet 42 feet 63metres 15 feet 30 feet 42 feet 70metres 15 feet 30 feet 43 feet 75metres 15 feet 32 feet 43 feet 80metres 15 feet 32 feet 44 feet 94metres 15 feet 33 feet 44metres 15 feet 34 feet 44metres 16 feet 34 feet 45In a design study for a device to generate electricity from wave power at sea,experiments were carried out on scale models in a wave tank to establishhow the choice of mooring method for the system affected the bending stressproduced in part of the device. The wave tank could simulate a wide rangeof sea states and the model system was subjected to the same sample ofsea states with each of two mooring methods, one of which was considerablycheaper than the other. The resulting data (from Hand et al., 1994, givingroot mean square bending moment in Newton metres) are shown in Table 3.2.The question of interest is whether bending stress differs for the two mooringmethods.Table 3.2:waves data. Bending stress (root mean squared bendingmoment in Newton metres) for two mooring methodsin a wave energy experiment.method1 method2 method1 method2 method1 method22.23 1.82 8.98 8.88 5.91 6.442.55 2.42 0.82 0.87 5.79 5.877.99 8.26 10.83 11.20 5.50 5.304.09 3.46 1.54 1.33 9.96 9.829.62 9.77 10.75 10.32 1.92 1.691.59 1.40 5.79 5.87 7.38 7.41The data shown in Table 3.3 were collected in an investigation of environmentalcauses of disease and are taken from Hand et al. (1994). They show theannual mortality per 100,000 for males, averaged over the years 1958–1964,and the calcium concentration (in parts per million) in the drinking water for61 large towns in England and Wales. The higher the calcium concentration,the harder the water. Towns at least as far north as Derby are identified in the© 2010 by Taylor and Francis Group, LLC