Oxygen

Oxygen was the only variable for which a statistically significant number of off-reservation sites showed either an upward or a downward trend.   Of the sites that showed a trend, the sites with increasing oxygen levels showed a marked predominance over those with decreasing oxygen levels.   This is unexpected, and contrasts with the results for the sites on the Ute Reservation.  Results for O2 trends at non-reservation sites are summarized in Table 8.

 

Table 12.  Summary of T-Test results, O2 for 147 off-reservation sites.

Significance Level

U

Number of Sites with Upward Trend

D

Number of Sites with Downward Trend

U+D

Number of Sites with Any Trend

Expected Number of Sites with Any Trend

Probability of U out of U+D Sites Increasing

(see Note 1)

Probability of U+D Sites with Any Trend

(see Note 2)

 

99.9%

2

0

2

0

0.250

8.05E-03

99.0%

8

0

8

1

0.004

6.47E-05

95.0%

26

1

27

7

2.0E-07

2.33E-09

 

Table 13.    Sen and Mann-Kendall statistics, O2 for 147 sites off the Southern Ute Reservation.

Significance Level

Sites with Positive Sen estimator

Sites with Negative

Sen estimator

 

Sites with Positive Mann-Kendall statistic

Sites with Negative Mann-Kendall statistic

99.0%

4

0

5

0

95.0%

19

5

19

8

Chi-square estimate of homogeneity for the Mann-Kendall scores: less than 0.0001%.