ISSS608 2017-18 T3 Assign Liu Yuanjing Methodology

 Investigating chemical contamination in the Boonsong Lekagul waterways

Background

Data and Methodology

Visualisations Analysis

Conclusion

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Tools

JMP Pro Tableau

Methodology

Methodology	Description
Standardization method:	Because we want to go through all measures in different waterways or locations but measures have different units and if we want see the volatility changes in different paths or location and then identify potential chemical contamination. Therefore, we decided to use Z-Score to modify the data bias. Z-score represents the distance of the original data from the mean, and the standard of the distance measure is the standard deviation. Z-score greater than zero indicates that the data is greater than the mean Z-score less than zero indicates that the data is less than the mean Z-score equal to zero indicates that the data is equal to the mean Z-score equal to "1" indicates that the data is one standard deviation larger than the mean Z-score equal to "-1" indicates that the data is one standard deviation smaller than the mean If the amount of statistical data is sufficient, the Z-score data distribution is satisfied, 68% of the data is distributed between "-1" and "1", and 95% of the data is distributed between "-2" and "2", 99%. The data is distributed between "-3" and "3". You can use this to verify your data. See the Z-score data distribution below: and then we edit the formula in tableau and add one measure variable, called “Z-Score”, the formula as below:
Animation analysis by Z-scores	In the dataset, there are more than 100 measures in different locations. Then when user to explore measures, it would kill lots of time to identify one by one. Therefore, Z-score could be utilized in making a preliminary screening among so many measures. In the data set, if measures z-score (based on its value) more than 1 or less than -1 would be classify “YES”, and if between [-1.1], would be labeled “NO”. The formula in tableau as below:
Path Analysis	Some of sampling sites are in the same water ways and part of them in the upper course, some in the middle course, and also have two sampling sites at lower course. And same waterflow (Path) could tell us the whole picture about chemical measures changes. Because the water would flow down along the path and the chemical contaminant also would flow down but a vital importance point needed to be consider is that the consist of chemical measures is always changing and many chemical substances would be diluted, as more tributaries along the path flow into the main stream. Therefore, it’s truly necessary for us to analysis from water path angle to digest the whole picture.
Location & Measures Analysis	Based on principle of prudence, we also need focus on every measures and invest it one by one to find the more accurately animation pattern. Because different chemical measures increase or decrease have uncertain positive or negative effects to water environment, so we cannot simply assume that the measures increase would cause negative effect to water environment. In this way, we analysis from location with detail value changes by every measure through the select functions.