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Most Current Cumulative Time Series Charts and Statistical Summaries
for NWQL LS 4437


The Time Series Charts
The charts provide OBSP recovery information for every analyte at different concentrations for every schedule OBSP assesses. The charts exhibit a Locally Weighted Scatterplot Smoothing (LOWESS) line. This line is used to help observe patterns and trends of the data over time. The time series charts also show bias and variability of the OSBP data. The most current time series charts in the table below will be overwritten periodically and will contain data that is currently being reviewed. All data is provisional and may change if the OBSP deems necessary.

There are two tables provided at the bottom of every time series chart that show statistical summaries.

Plotted Points Statistics Table
Description of the OBSP QA recoveries grouped by concentration level. The statistics in the table: mean, median, standard deviation and F-pseudosigma define bias and variability of the OBSP recoveries.

Sample Statistics Table
Counts (N) - The quantity of the variety of items.
Plotted - This number equals the total number in the above table.
Estimated Values - There are a number of reasons the laboratory will estimate (E) a result. If there are 100% of the results estimated the analyte is identified as a permanently estimated compound (analyte name in time series chart will be red).
Deleted Values - The laboratory may delete an entire sample or a single analyte for a number of reasons.
Spiked, Censored - A term for those samples that were spiked and correctly reported as less than a reporting level (possibly a raised reporting level) - the expected concentration was at a lower concentration than the censored result provided by the laboratory.
Spiked - The number of times the OBSP has submitted this analyte to the NWQL.
False Negative - The number of times the laboratory reports this analyte as not present in the sample when it is there.
Not Spiked - The number of times the OBSP has submitted a sample to the appropriate schedule, without this analyte.
False Positive - The number of times the laboratory reports this analyte as present when it is not in the sample.


The charts and data that you might secure from this U.S. Geological Survey (USGS) web page (identified as "OBSP") have not received official USGS approval and as such are provisional and subject to revision. The charts and data are released on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.

Lab Schedule 4437 - NAWQA Heat purgeable volatile organic compounds Preliminary Data (Unapproved)
Choose an analyte below or click here for all analytes sorted by NWQL parameter code Parameter CAS#
1,1-Dichloro-2-propanone 80336GM016 513-88-2
1,2,3-Trichloropropane 77443GM016 96-18-4
1,2-Dibromo-3-chloropropane 82625GM016 96-12-8
1,2-Dibromoethane 77651GM016 106-93-4
1,2-Dichloropropane 34541GM016 78-87-5
1,3-Dioxolane 81583GM016 646-06-0
1,4-Dioxane 81582GM016 123-91-1
1Methoxy-4(2-propenyl)benzene 68066GM016 140-67-0
1-octanol 77310GM016 111-87-5
2-ethoxyethyl acetate 68728GM016 111-15-9
2-hexanone, 5-methyl- 77179GM016 110-12-3
2-Nitropropane 77076GM016 79-46-9
2-pentanol, 4-methyl- 77113GM016 108-11-2
2-Propen-1-ol 68729GM016 107-18-6
4-heptanone, 2,6-dimethyl- 77419GM016 108-83-8
acetate, ethyl 81585GM016 141-78-6
acetate, isobutyl 77201GM016 110-19-0
acetate, isopropyl 45013GM016 108-21-4
acetate, propyl 45022GM016 109-60-4
acetonitrile 76997GM016 75-05-8
Acrolein 34210GM016 107-02-8
alpha-Terpineol 68730GM016 98-55-5
Butanal 68732GM016 123-72-8
butanol 77034GM016 71-36-3
Chloropicrin 77548GM016 76-06-2
cyclohexanone 77097GM016 108-94-1
diethylamine, n-nitroso- 78200GM016 55-18-5
Dimethoxymethane 81578GM016 109-87-5
Hexachlorocyclopentadiene 34386GM016 77-47-4
hexanol, 2-ethyl- 77311GM016 104-76-7
Isophorone 34408GM016 78-59-1
isopropyl alcohol 77015GM016 67-63-0
Methyl acetate 77032GM016 79-20-9
Nitrobenzene 34447GM016 98-95-3
n-Pentanal 77061GM016 110-62-3
tert-Butyl alcohol 77035GM016 75-65-0
tert-Butyl methyl ether 78032GM016 1634-04-4
trans-Crotonaldehyde 68733GM016 123-73-9

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