The Initial Estimates tab allows users to view plots of different variables in the main input dataset and view parameters in the model. Users can adjust initial estimates for the fixed effects to determine the best values.
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Use the pointer to move the Start Time and Duration sliders right or left to select which portion of the initial estimates time line to view, or type values into the fields beside the sliders. For example, if the total time line runs from 0–50, but you want to zoom in on 35–45. Set the start time to 35 and the duration to 10.
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Use the pointer to move the fixed effect slider right or left or adjust the initial estimates for each fixed effect, or type the values into the field beside the fixed effect slider.
Note:When typing a decimal value, be aware that typing an initial “0” will cause the checkbox to automatically become unchecked. Either drop the initial “0” when entering the value or recheck the checkbox.
By default, the fixed effect sliders do not allow users to select negative values. Moving the slider to the left changes the initial estimates to smaller decimal values. Clear the checkbox beside each fixed effect to allow the initial estimate to change to negative values.
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If different initial estimates are selected in the Initial Estimates tab, click the Copy to initial estimates
button to copy the initial estimate value to the Initial field for each parameter in the Fixed Effects tab.
If the initial estimates in the Fixed Effects tab match the initial estimates in the Initial Estimates tab, the Copy to initial estimates button is not available. -
In the plots menu
, select the different variables, parameters, and covariates used to create the plots.
The plots available in the Initial Estimates tab change depending on the type of dataset used, the type of model selected, and any additional parameters and covariates that are selected. For example, in a one-compartment PK model with IV bolus dosing and no extra parameters or covariates, users can select plots of C vs time, V vs time, Ke vs time, V vs C, and Ke vs C. -
Check the log checkbox if the Y axis is logarithmic.
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Check the overlay checkbox to create one plot that contains all profiles (will remove the previous, next, and trellis controls).
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Click prev to view the previous plot.
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Click next to view the next plot.
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Check the Same XY checkbox to use the same tick mark values on the X and Y axes.
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Click nX (+) to add a trellis row. This displays extra plots in the Initial Estimates tab.
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Click nX (-) to remove a trellis row.
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Click nY (+) to add a trellis column. This displays extra plots in the Initial Estimates tab.
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Click nY (-) to remove a trellis column.
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Increase the size of the Initial Estimates tab to expand the plot view.
Note:If the plotting window is not refreshed after making a change to the model structure or mappings, select a different tab and then go back to the Initial Estimates tab.
