Dear NM users,
During a pop PK model development, I found two parameters (based delta plots)
are highly correlated (positive correlation), therefore, I tried to add
Covariance between them in order to account for this correlation. However,
after this run, it turns out to be a negative correlation. Anybody had this
experience before? Could it be due to the model misspecification? Or dataset
does not support the IIV on these two parameters?
Any input is appreciated. Thank you in advance.
Jian
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