Chapter 10, Problem 10.26AC

54. Grip is applied to produce normal surface forces that compress the object being gripped. Examples include two people shaking hands, or a nurse squeezing a patient's forearm to stop bleeding. The article "Investigation of Grip Force, Normal Force, Contact Area, Hand Size, and Handle Size for Cylindrical Handles" (Human Factors, 2008: 734-744) included the following data on grip strength (N) for a sample of 42 individuals: 16 18 18 26 33 41 54 56 66 68 87 91 95 98 106 109 111 118 127 127 135 145 147 149 151 168 172 183 189 190 200 210 220 229 230 233 238 244 259 294 329 403 a. Construct a stem-and-leaf display based on repeat- ing each stem value twice, and comment on inter- esting features. b. Determine the values of the fourths and the fourthspread. c. Construct a boxplot based on the five-number sum- mary, and comment on its features. 5

The article "Bone Density and Insertion Torque as Predictors of Anterior Cruciate Ligament Graft Fixation Strength"t gave the accompanying data on maximum insertion torque (N• m) and yield load (N), the latter being one measure of graft strength, for 15 different specimens. Torque 1.8 2.2 1.9 1.3 2.1 2.2 1.6 2.1 1.2 1.8 2.6 2.5 2.5 1.7 1.6 Load 491 477 598 361 605 671 466 431 384 422 554 577 642 348 446 (a) Is it plausible that yield load is normally distributed? Yes, there are more than thirty data values. No, a normal probability plot of yield load is not quite linear. Yes, a normal probability plot of yield load is quite quadratic. No, there is not more than thirty data values. Yes, a normal probability plot of yield load is quite linear. (b) Estimate true average yield load by calculating a confidence interval with a confidence level of 95%. (Round your answer to two decimal places.) Interpret the interval. We are 95% confident that the true population average yield load lies below…

The depth of wetting of a soil is the depth to which water content will increase owing to extemal factors. The article "Discussion of Method for Evaluation of Depth of Wetting in Residential Areas" (J. Nelson, K. Chao, and D. Overton, Journal of Geotechnical and Geoenvironmental Engineering, 2011:293-296) discusses the relationship between depth of wetting beneath a structure and the age of the structure. The article presents measurements of depth of wetting, in meters, and the ages, in years, of 21 houses, as shown in the following table. Age Depth 7.6 4 4.6 6.1 9.1 3 4.3 7.3 5.2 10.4 15.5 5.8 10.7 4 5.5 6.1 10.7 10.4 4.6 7.0 6.1 14 16.8 10 9.1 8.8 Compute the least-squares line for predicting depth of wetting (y) from age (x). b. Identify a point with an unusually large x-value. Compute the least-squares line that results from deletion of this point. Identify another point which can be classified as an outlier. Compute the least-squares line that results from deletion of the outlier,…