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This Appendix summarizes the statistical analysis applied to the data. The results of statistical analysis of the plate count data by the paired t-test and the
Wilcoxon signed ranks test is presented. This analysis
utilized Systat ® computer software. The plate count data
for the product water, Run 1 and Run 2, was also analyzed
with standard error bars.
The application of the paired t-test necessarily assumes the samples were independent and that the data is normally distributed. This parametric analysis of the data may not be as appropriate as the non-parametric Wilcoxon signed ranks test.
TABLE A.l PAIRED SAMPLES T-TEST ON RUN 1 PRODUCT WATER DATA 2 GPM/sq ft vs 4 GPM/sq ft 2 6 cases Mean Difference = 2555.462 SD Difference = 25269.022 T = 0.516 DF = 25 Prob = 0.611 2 GPM/sq ft vs 6 GPM/sq ft 26 cases Mean Difference = 13487.192 SD Difference = 22577.847 T = 3.046 DF = 25 Prob = 0.005 4 GPM/sq ft vs 6 GPM/sq ft 26 cases Mean Difference = 10931.731 SD Difference = 17596.652 T = 3.168 DF = 25 Prob = 0.004
2 GPM/sq ft 0
4 GPM/sq ft 10
6 GPM/sq ft 6
TABLE A.2 WILCOXON SIGNED RANKS TEST ON RUN 1 PRODUCT
WATER DATA
Counts of Differences (Row Variable Greater Than Column)
2 GPM/sq ft 4 GPM/sq ft 6 GPM/sq ft 15 19
0 20 4 0
Z = (Sum of Signed Ranks)/Square Root(Sum of Squared Ranks)
2 GPM/sq ft 4 GPM/sq ft 6 GPM/sq ft
.000
-3.386 .000
Two-sided Probabilities Using Normal Approximation
2 GPM/sq ft 4 GPM/sq ft 6 GPM/sq ft 2 GPM/sq ft 1.000 4 GPM/sq ft 0.142 1.000 6 GPM/sq ft 0.004 0.001 1.000 2 GPM/sq ft .000 4 GPM/sq ft -1.467 6 GPM/sq ft -2.894
TABLE A. 3 PAIRED SAMPLES T-TEST ON RUN 2 PRODUCT WATER DATA CI2 VS BW-24 hr. 34 cases Mean Difference = -13790.059 SD Difference = 11861.614 T = 6.779 DF = 33 Prob = 0.000 C12 VS BW-48 hr. 34 cases Mean Difference = -16065.353 SD Difference = 12991.313 T = 7.211 DF = 33 Prob = 0.000 BW-24 hr. VS BW-48 hr. 34 Cases Mean Difference = -2275.294 SD Difference = 9611.408 T = 1.380 DF = 33 Prob = 0.177
TABLE A.4 WILCOXON SIGNED RANKS TEST ON RUN 2 PRODUCT
WATER DATA
Counts of Differences (Row Variable Greater Than Column) CI2 BW-24 hr. BW-48 hr.
Clo 0 3 1
BW-24 hr. 31 0 12 BW-48 hr. 33 21 0
Z = (Sum of Signed Ranks)/Square Root(Sum of Squared Ranks) CI2 BW-24 hr. BW-48 hr.
CI2 0.000
BW-24 hr. 4.693 0.000
BW-48 hr. 4.984 1.885 0.000
Two-sided Probabilities Using Normal Approximation
CI2 BW-24 hr. BW-48 hr,
CI2 1.000
BW-24 hr. 0.000 1.000
180 - r 160 140 — J---1i— n T J 120 — U L 4 r 100 - U 80 - 60 - 40 20 1 + , 1 .J_ 1 1 1 1 !...1 -+- 1
1 +
-B- , 1 1 1 1 1 1 7 22 27 29 38 43 45 49 52 57 78 80 83 85 87 90 92 94 97 99 101113115118120122 DAY OF RUND +1 SE D -1 SE + MEAN
160 - 140 -
7 22 27 29 38 43 45 49 52 57 78 80 83 85 87 90 92 94 97 99 101113115118120122
DAY OF RUN