Exercise 3.14: Moore (1975) reported the results of an experiment to construct a model for total oxygen demand in dairy wastes as a function of five laboratory measurements (Exhibit 3.7). Data were collected on sam- ples kept in suspension in water in a laboratory for 220 days. Although all observations reported here were taken on the same sample over time, assume that they are independent. The measured variables are: log(oxygen demand, mg oxygen per minute) biological oxygen demand, mg/liter y 21 I2 total Kjeldahl nitrogen, mg/liter 23 total solids, mg/liter 24 total volatile solids, a component of 23, mg/liter chemical oxygen demand, mg/liter I5 1. Fit a multiple regression model using y as the dependent variable and all x;'s as the independent variables. 2. Now fit a regression model with only the independent variables x3 and 5. How do the new parameters, the corresponding value of R and the t-values compare with those obtained from the full model? 3 Day #1 22 y 0 1125 232 7160 85.9 8905 1.5563 4 25 15 7 920 268 8804 86.5 7388 835 271 8108 85.2 5348 0.8976 0.7482 37 44 58 65 72 80 86 93 100 107 122 129 151 171 220 22 1000 237 6370 83.8 8056 29 1150 192 6441 82.1 6960 990 202 5154 79.2 5690 840 184 5896 81.2 6932 0.1139 650 200 5336 80.6 5400 0.1139 640 180 5041 78.4 3177 -0.2218 583 165 5012 79.3 4461 -0.1549 570 151 4825 78.7 3901 0.0000 570 171 4391 78.0 5002 0.0000 510 243 4320 72.3 4665 -0.0969 555 147 3709 74.9 4642 -0.2218 460 286 3969 74.4 4840 -0.3979 275 198 3558 72.5 4479 -0.1549 510 196 4361 57.7 4200 -0.2218 165 210 3301 71.8 3410 -0.3979 244 327 2964 72.5 3360 -0.5229 79 334 2777 71.9 2599 -0.0458 0.7160 0.3130 0.3617 EXHIBIT 3.7: Data on Oxygen Demand in Dairy Wastes URCE: Moore (1975). Reproduced with permission of the auth