Using weights


Period04 does also handle weighted data. It recognizes three different types of weights:
In order to use weights the user has to:
  1. set or read in weights (which will be described below)
  2. activate them for calculations
    This can be done in the "Weight selection dialog" which can be accessed by the "Special" menu or via the shortcut "Ctrl+W".

Using point weights:


As "point weight" we denote weights that are assigned to each of your data points. Point weights can only be read in along with time string data. To include these data proceed as described here:
  1. Click on the button "Import time string" and select the file that contains your data set in the file-selector dialog.
  2. Now another dialog appears. It will show the columns in your data file and asks you to label these columns correctly. Specify the column that contains the point weight data as "Pnt.weight" and select appropriate labels for the other columns too - at least "Time" and "Observed" are required. Press "OK".
  3. Although your data set has been read in, the program does not yet include the point weights in calculations. They have to be activated in the "Weight selection dialog" first. So open the dialog, select "Point weight" and press "OK". From this point the program will use the weighted data until you deselect this option.

Using deviation weights:


The deviation weights are calculated from the residuals of data points:
In order to use deviation weights open the "Weight selection dialog", select "Deviation weight" and set an appropriate cutoff value.

Using attribute weights:


Each of the four list boxes in the Time string tab represents an attribute. The default names of these attributes are "Date", "Observatory", "Observer" and "Other". If the time string has been subdivided in at least one attribute it is possible to give each substring a certain weight.
  1. If you havn't done so already, read in a time string.
  2. Subdivide the time string. Let us assume that you divided the time string into several substrings in the attribute "Date".
  3. Select a substring for which you want to change the weight. Open the "Edit substring properties" menu by pressing the "Edit substring" button at the bottom of the "Date" list box. You can also access this dialog directly via the pop-up menu.
  4. Type the new weight value into the respective field and press "OK".
  5. To enable the weights assigned to substrings of attribute "Date" open the "Weight selection dialog", select "Date" and press "OK". Now these weights will be included in all calculations.