The influence of age and race on primary outcome variables were further explored in models restricted by age and race.
Since some of the area means did not have a variance (when they came from only one observation), we examined the effect of missing variances by fitting another model restricted to data sets that had non-missing variances.
However, the use of the PMF-56 model is restricted by the unavailability of input climatic variables in many locations and the option is to use simple approaches with limited data requirements.
This model is restricted by the following constraints or assumptions: 1.
Our choice of variables and the econometric model were restricted by the explanatory variables available in the database.
In addition, the number of variables included in the regression model was restricted by the sample size and statistical considerations.
In our present study, there was a difficulty to detecting murine cytotoxic T cells, because the recognition of antigens by CTLs in a mouse model is restricted by self class I/II MHC alleles.
However, the use of murine models is restricted by costs, the requirement of specialized facilities and personnel, legal requirements and ethical considerations.
Although many successful attempts have been made, a wider application of theoretical models is restricted by their heavy demand in terms of computing capacity and time.
34 35 Since the amount of effect modifiers included in the models is restricted by the total number of patients included for analysis, the optional patient-specific effect modifiers will only be included if sufficient patient data are available.
