All categorical predictors were modelled using dummy variables, while all continuous predictors were modelled using restricted quadratic splines (Greenland, 1995) based on 2 knots for the tertiles to relax linearity assumptions.
To test the effect modification (interactions), simple categorical models based on stratification were constructed first, followed by logistic regression models using dummy variables.
Although the baseline hazard can be modelled using dummy variables for each time interval, in practice efficient estimates of model parameters can be obtained using low order polynomials for the time [ 35].
The models included prognostic factors (postoperative breast radiotherapy, pathological tumor size, histologic type, receptor status) modeled using dummy variables, and also propensity score as a linear term to adjust for imbalances in baseline variables influencing the decision to perform axillary dissection.
This is verified experimentally and modelled by using dummy circuits and a finite element model.
All variables with a LRTS of less than 0.2 were put forward into the multivariable model, including recoding using dummy variables of categorical groups appearing to show some evidence of association (Table 4).> The final multivariable model indicated five variables to be significantly associated with the likelihood of a case being classified as critical (Table 5).
The Type C models were fitted using dummy variables for each region coded 1 for PSPs within the region and 0 otherwise.
This could be done by adjusting for each stratum in a regression model using three dummy variables, but is often done by performing the analysis within each stratum, and combining the results.
In addition, the probit model was re-estimated using dummy variables replacing the continuous variable.
Primary outcomes, such as 24-hour UUN levels, nitrogen balance, serum albumin concentrations, and prealbumin concentrations were analyzed with a generalized linear model for repeated measures using dummy variables.
