Suppose your task is to estimate the total phosphorous in the water of a pond. D
ID: 3183129 • Letter: S
Question
Suppose your task is to estimate the total phosphorous in the water of a pond. Data from similar ponds suggests that phosphorous concentration may be higher at depth than near the surface. Hence the pond is divided into 3 depth strata: a surface layer, a bottom layer, and the intermediate zone. Within each stratum 1-L water samples are taken at random locations with respect to depth and horizontal position. The phosphorous concentration of a 100-mL aliquot from each 1-L sample will be measured. The target population is the total number of N of 100-mL water samples in the pond. The number of such aliquots in stratum h is N_h. Suppose the funds available for sampling will allow for n = 30 samples and that proportional allocation to the 3 strata is used. Table 1. Gives the values of N_h for the pond along with the resulting values of n_h, Calculate the values listed in the remaining columns.Explanation / Answer
Strata Nh Wh nh 1 3940000 0.409 12 2 3200000 0.332 10 3 2500000 0.259 8 Sum 9640000 1 30 x-bar_h Nh*x-bar_h S2h Wh*x-bar_h W2h*S2h/nh 2 7880000 0.4299242 0.818 0.014653251 3.84 12288000 0.4134444 1.27488 0.013726356 5.26 13150000 1.2941071 1.36234 0.041896719 I = 33318000 (x-bar)st = 3.45522 S2(x-bar)st = 0.070276
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.