PEST requires that observations be assigned to observation groups so now we need to define the observation groups. We do this in the PEST Properties dialog box. Select Model|Pest Properties and select the Observation Group Properties pane, change the number of observation groups, and specify the names of the observation groups: Heads, CHD, and Comparison as illustrated below. The use of separate observation group names is not required for the parameter estimation but is recommended because it facilitates tracking how well different observation types are being simulated.
Screen capture of the "Pest Properties" dialog box illustrating the definition of the observation groups. "Heads," "CHD," and "Comparison" are listed in the fields under the "Observation Group Name" column head.
Next go to the Observation group assignments tab, expand the list labeled (none), and select all the head observations. You can select them by clicking on the first one, holding the shift key down and then clicking on the last one. Then click down on one of them again and while holding the mouse button down, drag the cursor down to the Heads group and release the mouse as illustrated below. Assign the other two observations to the CHD and Comparison groups respectively.
Screen capture of the "Pest Properties" dialog box illustrating assigning observation groups. "Head_Obs1" through "Head_Obs8" are highlighted and the cursor is shown as dragging them to the "Heads" group in the directory.