Documentation Guide for Use of Boxplots

Document Sample
Documentation Guide for Use of Boxplots Powered By Docstoc
					Documentation Guide for Use of Boxplots.xls

The formulas used in Boxplots.xls assist in the production of annual sea surface
temperature and salinity boxplot graphs. It is not compulsory to use these plots,
however boxplot representation of the data is required (see Monitoring Design
Template.doc). Presenting the data in this form allows for ease of interpretation of the
variability in the data throughout the year and between years.
Location specific annual sea surface temperature ( oC) and salinity(ppt) should be
respectively input into the Temperature data and Salinity data worksheets. Citation of
the years the data represents should be included along with the source of the
information.
The Temperature and Salinity Boxplot sheets contain the formulas required to
produce the boxplots. Definition of the “Statistic” column is as follows:
-   Lower quartile – 25th percentile of each month. This is the lower limit of the box.
-   Upper quartile – 75th percentile of each month. This is the upper limit of the box.
-   Lower whisker – 5th percentile of each month. This is the limit of the lower arm
    extending from the box.
-   Upper whisker – 95th percentile of each month. This is the limit of the upper arm
    extending from the box.
-   Median – the median value for each month. This is the line contained within the
    box.
-   Minimum – this is the minimum value for each month. This is the dot beneath the
    lower whisker
-   Maximum – this is the maximum value for each month. This is the dot above the
    upper whisker
Once the new data is input, the graphs will automatically update to present the new
data. These graphs should then be copied and inserted into the Monitoring Design
Template. If the graphs do not appear to be appropriately representing the data,
ensure that the data range in the formulas is capturing the entire data range.
Appropriate minimum and maximum values should then be selected to use as the
environmental ranges of the monitoring locations. Note: if the range selected appears
to be unrepresentative of the data range (i.e. an outlier), the selected temperature or
salinity range may be questioned by reviewers and amendment may be required.