.1. Earthquake records. Measurements of engineering interest have been recorded during earthquakes in Japan and in other parts of the world since 1800. One of the critical recordings is of apparent relative density, RDEN. After the com- mencement of a strong earthquake, a saturated fine, loose sand undergoes vibra- tory motion and consequently the sand may liquefy without retaining any shear strength, thus behaving like a dense liquid. This will lead to failures in structures supported by the liquefied sand. These are often catastrophic. The standard pen- etration test is used to measure RDEN. Another measurement taken to estimate the prospect of liquefaction is that of the intensity at which the ground shakes. This is the peak surface acceleration of the soil during the earthquake, ACCEL. The data are from J. T. Christian and W. F. Swiger (1975), J. Geotech. Eng. Div., Proc. ASCE, 101, GT111, 1135–1150, and are reproduced by permission of the publisher (ASCE): RDEN ACCEL (units of g) RDEN ACCEL RDEN ACCEL (%) (%) (units of g) (%) (units of g) 53 0.219 30 0.138 50 0.313 64 0.219 72 0.422 44 0.224 0.556 0.447 53 0.146 90 100 0.231 64 0.146 40 65 0.334 65 0.684 50 0.547 68 0.419 55 0.611 55 0.204 78 0.352 75 0.591 50 0.170 58 0.363 72 0.522 0.258 0.250 55 0.170 80 0.291 40 75 0.192 55 0.314 58 53 0.292 100 0.377 43 0.283 70 0.299 100 0.434 32 0.419 64 0.292 52 0.350 40 0.123 53 0.225 58 0.334 Note: g denotes acceleration due to gravity (9.81 m/s²). Compute the sample mean F , standard deviation §, and the coefficient of skewness, 81, for RDEN and ACCEL. Construct stem-and-leaf plots for each set. Comment on