Polyester fiber ropes are increasingly being used as components of mooring lines for offshore structures in deep water. The authors of the paper “Quantifying the Residual Creep Life of Polyester Mooring Ropes” (Intl. J. of Offshore and Polar Exploration, 2005: 223–228) used the accompanying data as a basis for studying how time to failure (hr) depended on load (% of breaking load):
X | 77.7 | 77.8 | 77.9 | 77.8 | 85.5 | 85.5 |
y | 1 5.067 | 552.056 | 127.809 | 7.611 | .124 | .077 |
X | 89.2 | 89.3 | 73.1 | 85.5 | 89.2 | 85.5 |
y | .008 | .013 | 49.439 | .503 | .362 | 9.930 |
x | 89.2 | 85.5 | 89.2 | 82.3 | 82.0 | 82.3 |
y | .677 | 5.322 | .289 | 53.079 | 7.625 | 155.299 |
A linear regression of log(time) versus load was fit. The investigators were particularly interested in estimating the slope of the true regression line relating these variables. Investigate the quality of the fit, estimate the slope, and predict time to failure when load is 80, in a way that conveys information about reliability and precision
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Chapter 13 Solutions
PROBABILITY & STATS FOR ENGINEERING &SCI
- What does the y -intercept on the graph of a logistic equation correspond to for a population modeled by that equation?arrow_forwardQ5) An article in the ACI Materials Journal (Vol. 84, 1987, pp. 213–216) describes several experiments investigating the rodding of concrete to remove entrapped air. A 3-inch & 6-inch cylinder was used, and the number of times this rod was used is the design variable. The resulting compressive strength of the concrete specimen is the response. The data shown is posted on BruinLearn Week 2: A. Is there any difference in compressive strength due to the rodding level? Use (α= 0.05). B. Find the P-value for the F statistic in part (a). C. Analyze the residuals from this experiment. What conclusions can you draw about the underlying model assumptions? D. Construct a graphical display to compare the treatment means as described in your lecture notes.arrow_forwardPlease help me with this problem and i needed only part d and e only please.... Very urgentarrow_forward
- 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,…arrow_forward5.2arrow_forwardAttached to the end of the page is a portion of a printout from a stepwise regression analysis. a) Any of the F statistics on the printout can be computed via the formula: F = (SSReg( Model A ) – SSReg( Model B ) ) / C MSResidual( Model A) Identify what Model A, Model B, and the constant C are in order to obtain the F = 1.33 value for the variable x8 . b) Based on the printout for Step 6 of the stepwise selection procedure, what will be the next change in the model, in Step 7 of the procedure? (In other words, will a particular term be dropped, or added, or will nothing occur? Assume that the significance level for entry and staying are a = .15.)arrow_forward
- The article “‘Little Ice Age’ Proxy Glacier Mall Balance Records Reconstructed from Tree Rings in the Mt. Waddington Area, British Columbia Coast Mountains, Canada” (S. Larocque and D. Smith, The Holocene, 2005:748–757) evaluates the use of tree ring widths to estimate changes in the masses of glaciers. For the Sentinel glacier, the net mass balance (change in mass between the end of one summer and the end of the next summer) was measured for 23 years. During the same time period, the tree ring index for white bark pine trees was measured, and the sample correlation between net mass balance and tree ring index was r = −0.509. Can you conclude that the population correlation ρ differs from 0?arrow_forwardThe article "Modeling Resilient Modulus and Temperature Correction for Saudi Roads" (H. Wahhab, I. Asi, and R. Ramadhan, Journal of Materials in Civil Engineering, 2001:298– 305) describes a study designed to predict the resilient modulus of pavement from physical properties. The following table presents data for the resilient modulus at 40°Cin10® kPa (y), the surface area of the aggregate in m²/kg (x1), and the softening point of the asphalt in °C (х). y X1 X2 1.48 5.77 60.5 1.70 7.45 74.2 2.03 8.14 67.6 2.86 8.73 70.0 2.43 7.12 64.6 3.06 6.89 65.3 2.44 8.64 66.2 1.29 6.58 64.1 3.53 9.10 68.6 1.04 8.06 58.8 1.88 5.93 63.2 1.90 8.17 62.1 1.76 9.84 68.9 2.82 7.17 72.2 1.00 7.78 54.1 The full quadratic model is y = + P,x, + PzX, + Pz*jXz + Pxx¡ + Bzx; + €. Which submodel of this full model do you believe is most appropriate? Justify your answer by fitting two or more models and comparing the results.arrow_forwardLecture(8.8): The amount of time people engage in physical activity mat be related to health outcome. Those who report that they spend more than 15 hours are put into one while those who spend less 10 were put into another group. (Those who fall in between 10 and 15 were left out of the study); The reaearcher then ask the participants to wear a monitor for one month. The average time in minutes is recorded and shown below . Is there any evidence that on average people who watch less than 10 hours watching televsion spend more time on physical activity.?. Test the hypotheses at (alpha=0.05) using the 5 step procedure <10 hours 75 63 118 35 82 >15 hours 62 6 78 43 22 33arrow_forward
- The article "Modeling of Urban Area Stop-and-Go Traffic Noise" (P. Pamanikabud and C. Tharasawatipipat, Journal of Transportation Engineering, 1999:152–159) presents measurements of traffic noise, in dBA, from 10 locations in Bangkok, Thailand. Measurements, presented in the following table, were made at each location, in both the acceleration and deceleration lanes. Location Acceleration Deceleration 78.1 78.6 78.1 80.0 3 79.6 79.3 4 81.0 79.1 78.7 78.2 78.1 78.0 78.6 78.6 78.5 78.8 78.4 78.0 10 79.6 78.4 Can you conclude that there is a difference in the mean noise levels between acceleration and deceleration lanes?arrow_forwardPlease use the accompanying Excel data set or accompanying Text file data set when completing the following exercise. An article in Wood Science and Technology, "Creep in Chipboard, Part 3: Initial Assessment of the Influence of Moisture Content and Level of Stressing on Rate of Creep and Time to Failure" (1981, Vol. 15, pp. 125-144) studied the deflection (mm) of particleboard from stress levels of relative humidity. Assume that the two variables are related according to the simple linear regression model. The data are shown below x = Stress level (%) 54 54 61 61 68 68 75 75 75 y = Deflection (mm) 16.473 18.693 14.305 15.121 13.505 11.64 11.168 12.534 11.224 a. Calculate the least square estimates of the intercept (a) and slope (b). What is the estimate of o (c)? b. Find the estimate of the mean deflection if the stress level can be limited to 61% (d). c. Estimate the change in the mean deflection associated with a 7% increment in stress level (e). (a) i (Round your answer to 2…arrow_forwardPlease use the accompanying Excel data set or accompanying Text file data set when completing the following exercise. An article in Wood Science and Technology, "Creep in Chipboard, Part 3: Initial Assessment of the Influence of Moisture Content and Level of Stressing on Rate of Creep and Time to Failure" (1981, Vol. 15, pp. 125-144) studied the deflection (mm) of particleboard from stress levels of relative humidity. Assume that the two variables are related according to the simple linear regression model. The data are shown below x = Stress level (%) 54 54 61 61 68 68 75 75 75 y = Deflection (mm) 16.473 18.693 14.305 15.121 13.505 11.64 11.168 12.534 11.224 a. Calculate the least square estimates of the intercept (a) and slope (b). What is the estimate of o² (c)? b. Find the estimate of the mean deflection if the stress level can be limited to 66% (d). c. Estimate the change in the mean deflection associated with a 8% increment in stress level (e). (a) i (Round your answer to 2…arrow_forward
- Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage LearningGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill