Dissolved Oxygen Lab Report
As for the results of our tests, we came up with interesting findings. For the first test we conducted, pH, we came up with statistically significant results. Our p-value was .002, well below the .05 threshold. The control group’s mean pH was 6.65, whereas the experimental group’s was 6.46. This resulted in a change in pH of .19, making the water more acidic. As for the Q-values, the control group’s had a Q-value of 81 and the experimental had a Q-value of 75, that’s a decrease of 6, a significant statistic (Figure 1). For the next test, Dissolved Oxygen, we also created a bar graph to compare the values for the control and experimental groups. These results came in as statistically significant too, as the p-value was very low at .004. As for the overall mean values of the two groups, we found that the control group was oversaturated with oxygen at 102.78% while the experimental group was also slightly oversaturated at 101.55%.
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This means that the addition of E.
coli lowered the Dissolved Oxygen by 1.23%. Based on WQI calculations, the control group had a Q-value of 98 and the experimental group had a Q-value of 99. Resulting in an increase of water quality by 1 (Figure 2). The testing for Turbidity also proved to be statistically significant. Our p-value for this test which showed that the difference between the sample means between the two groups was significant was .006. Also for the control group, the turbidity level was measured to be 3.23NTU and the Q-value for the control was 89. Whereas the experimental group had a turbidity level of 5.63NTU and a Q-value of 84. This resulted in a difference in turbidity that was 2.40NTU and a difference in Q-value that was 5. By raising the E. coli levels, we successfully raised turbidity and lowered the Q-value (Figure 3). The only test we conducted that was not statistically significant was our CFU assay. The overall CFU/100mL of the control group was 808,183, while the value for the experimental group was
2,450,000. This resulted in an increase of colonies by 1,641,816, a very large number. The Q-values for these groups was irrelevant because our findings were not statistically significant. The p-value for this test was .143, which is above the .05 threshold making it not statistically significant (Figure 4).
This means that the addition of E.
coli lowered the Dissolved Oxygen by 1.23%. Based on WQI calculations, the control group had a Q-value of 98 and the experimental group had a Q-value of 99. Resulting in an increase of water quality by 1 (Figure 2). The testing for Turbidity also proved to be statistically significant. Our p-value for this test which showed that the difference between the sample means between the two groups was significant was .006. Also for the control group, the turbidity level was measured to be 3.23NTU and the Q-value for the control was 89. Whereas the experimental group had a turbidity level of 5.63NTU and a Q-value of 84. This resulted in a difference in turbidity that was 2.40NTU and a difference in Q-value that was 5. By raising the E. coli levels, we successfully raised turbidity and lowered the Q-value (Figure 3). The only test we conducted that was not statistically significant was our CFU assay. The overall CFU/100mL of the control group was 808,183, while the value for the experimental group was
2,450,000. This resulted in an increase of colonies by 1,641,816, a very large number. The Q-values for these groups was irrelevant because our findings were not statistically significant. The p-value for this test was .143, which is above the .05 threshold making it not statistically significant (Figure 4).